Amsterdam was a bad place to be in the winter of 1944–1945, especially if you were a pregnant mother. It was the beginning of the Dutch Hunger Winter. The Allied invasion of Normandy the previous June eventually gave relief to the Dutch, but in its immediate aftermath it brought misery. The Allies had been blocked at the Rhine and could not free much of the Netherlands from German occupation. In September the exiled Dutch government in London ordered railway workers in the Netherlands to go on strike in order to aid the Allies. They duly followed instructions, but the result was disastrous. German administrators retaliated with a food blockade, cutting off the western Netherlands from its food supplies.1
It went from bad to worse. First, winter came very early that year and was unrepentantly harsh. Canals froze over. Food could not be transported. Retreating German troops destroyed bridges and docks, making transportation even more difficult. Second, much of the arable land had been ravaged by warfare and was barren—unable to provide sustenance for the Dutch citizenry. Two more painful blows to aching, empty stomachs.
People began to starve. In November, city residents were rationed only 1,000 kilocalories of food a day. By February 1945 conditions deteriorated further with diets dropping to 580 kilocalories a piece.2 Ten thousand died of malnutrition, particularly in the cities, which were cut off from the countryside and food. Many thousands more are thought to have died of complications as a result of the famine.3 And for the remaining millions, life was wretched and depressing. Relief came only with liberation, in May 1945—ending a bitter eight months for the Dutch people.
This seems a peculiar starting point for a window into antisocial personality, but the seeds of violence were being sown in that harsh winter, concealed in out-of-sight little victims—the unborn babies of starved, pregnant women. We know this because in 1963, when the male babies who were in utero during the famine turned eighteen, they underwent compulsory military service, and at that time they were subjected to a psychiatric examination that included formal assessment of antisocial personality disorder.4 Data collected from these examinations became the foundations of a unique epidemiological study on the effects of prenatal malnutrition on later behavior.
In this breakthrough research study, Richard Neugebauer and colleagues from the New York State Psychiatric Institute conducted detailed analyses on these data. They divided the enormous sample of 100,543 men into those who were exposed to the famine—especially in the large cities in the west, including Amsterdam, Rotterdam, Leiden, Utrecht, and the Hague—and those in the north and south who were not exposed to the famine.5 The key result? Those exposed to the famine were two and a half times more likely to develop antisocial personality disorder in adulthood than those not exposed to the famine. The effects being especially true if the food shortage occurred during the first or second trimester of pregnancy. These findings were the first to demonstrate that poor nutrition during pregnancy predisposes to antisocial behavior in the offspring.
This chapter on nutrition, toxins, and mental health is yet another that highlights the importance of the environment in causing the brain impairments that can contribute to crime. From the gut to the teeth to the hair and back to the brain, this particular close-up of the anatomy of violence shows that human and animal studies are building a persuasive picture of how a lack of iron, zinc, protein, riboflavin, and omega-3 in our diets may dump some of us into the violence trash bin. It’s a question of how both too little and too much food is bad for us. We’ll also see that these dietary deficiencies can be compounded by an overexposure to heavy metals in the environment, including lead and manganese. Finally, we’ll round off this physical-health perspective with a mental-health perspective, showing how major mental illness, with its base in biology, also contributes to violence.
My own research into nutritional deficiencies and violence was inspired during a visit with Danny Pine, a brilliant and energetic researcher at Columbia University who had been working on heart rate and cognitive functioning in conduct-disordered children. We were walking to a meeting with Neugebauer, and Danny, with his sparkling glasses and wild beard, which had a life of its own, was talking a mile a minute, as he often does. “And Adrian, you just have to meet Richard. What a story from Holland—World War II, starvation, crime. It’s really something, you’re gonna love this.” And then he added with a mysterious twinkle and a wry smile, “Don’t forget to ask him about the tulip bulbs.”
Tulips? What’s that all about? That song “When it’s spring again, I’ll bring again tulips from Amsterdam” flashed through my mind—but how does that fit into an academic meeting on violence? That was as much as Danny left me with before I met Richard Neugebauer and heard firsthand the astonishing story of the Dutch Winter Famine—and the tulip bulbs. Apparently, in the final months of the food blockade the starving Dutch began to eat tulip bulbs. These are toxic, and as we shall see later in this chapter, toxins have been associated with offending. Richard acknowledged that other issues remained unresolved. Only male adults had been studied. What about females? Could this malnutrition story apply to aggressive and antisocial behavior in children? And do social factors like poverty play a hidden role?
These were the issues that percolated through my mind and ultimately stimulated us to look into nutrition in our Mauritius study. When our subjects were three years old, 1,559 of them came to the laboratory with their mothers to be examined by a pediatrician. We looked for five internal and external signs of malnutrition. First, they had their blood analyzed in a lab to assess hemoglobin levels. This gave us a handle on iron deficiency. Second, we had pediatricians conduct a physical examination of each child to look for four other external signs of malnutrition. Do you ever remember as a kid having cracks at the corners of your mouth? I seemed to have them on and off, and I’d poke them with my tongue when they felt hard and dry in order to soften them up. This is angular stomatitis, caused by a riboflavin deficiency, specifically a deficit in vitamin B2, but it can also reflect niacin deficiency.6
Then the pediatrician would take a good look at the child’s hair. What color was it? In Mauritius, almost all of the children have black hair because they are of Indian, African, or Chinese extraction. But some kids had an orange tinge to their hair. It wasn’t some kind of funky look that their parents gave them to make them look cute and artsy—it was kwashiorkor. This is African dialect referring to “red hair.” It’s a sign of zinc, copper, and protein malnutrition that causes dyspigmentation of the hair—essentially a loss of the natural black color.7 The pediatrician also looked to see if the hair was sparse and thin, a sign of zinc, iron, and protein deficiency.8 Then, after these two careful looks, the pediatrician would grab a piece of hair and give it a tug. If it came out easily, it was a sign of protein energy malnutrition.9 There we have the five strands—all clinical indicators of malnutrition.
At this point, Jianghong Liu, who at that time was a research fellow at the University of Southern California, entered the picture. She was the driving force behind the results I’ll discuss here. If a child had any one of these significant indicators, she assigned them to the malnourished group. Those who lacked malnutrition were the normal controls. She assessed the kids again at ages eight, eleven, and seventeen, the ages at which we had obtained teacher and parent ratings of their aggressive, antisocial, and hyperactive behavior. The results are shown in Figure 7.1. As you can see, at every single age the malnourished kids had higher scores on all dimensions of what we call “externalizing behavior”—aggression, delinquency, and hyperactivity.10
Hold on a second. Aren’t kids with poor nutrition more likely to have parents with low levels of education and income? And aren’t low levels of education and income social risk factors for childhood behavior problems? Maybe poor nutrition itself makes no active contribution to aggression, but is linked to social deprivation, which causes aggression. Point taken. So Jianghong Liu controlled for poverty and twelve other social factors that could be driving the increase in aggressive behavior in the malnourished kids. The result? The malnutrition-aggression link was obstinate—it just would not budge. And it did not matter whether you were Creole or Indian, a boy or a girl. Poor nutrition does not respect race or gender when it comes to raising the risk of aggression. Furthermore, we also saw a dose-response relationship at age seventeen. If you look at Figure 7.2 you’ll see that the more signs of malnutrition the child had, the higher the score for conduct disorder. This result really reinforces the link between malnutrition and conduct disorder.
Figure 7.1 Scores on externalizing behavior problems in malnourished and control groups across three time periods
The type of malnutrition the kids had did matter a bit, though. Iron deficiency was especially important. This ties in with findings from experimental studies on animals showing that iron is involved in DNA synthesis, neurotransmitter production and functioning,11 and white-matter formation in the brain.12 If iron benefits the brain, low iron should be a problem. And it is. Experimental studies that have supplemented children’s diets with iron show improved cognitive functioning.13 My angular stomatitis, which reflected a vitamin B2 deficiency, would also play a helping hand in poor cognition, because vitamin B2 enhances the hematological response to iron.14 Consequently, riboflavin deficiency would reduce iron and further negatively affect cognition. Eat your vitamin-fortified cardboard cornflakes.
It really does seem that poor nutrition, right across the board—across ages and types of problem behaviors—raises the odds of behavior problems in the growing child. But we get back again to a central, fundamental question. What is the mechanism of action, the way in which nutrition—or rather the lack of it—translates itself into aggressive and antisocial behavior? Back to basics. Back to the brain, and back to cognitive functioning.
Figure 7.2 Dose-response relationship between signs of malnutrition at age three and behavior problems at age seventeen
Jianghong Liu found that the children with poor nutrition at age three also had lower IQs at that age and eight years later at age eleven. She again found a dose-response relationship, with increasing levels of malnutrition resulting in decreasing scores on IQ. If a child had three indicators of malnutrition, her IQ dropped seventeen points. It’s a significant tumble: imagine being average in your class and dropping to the bottom 11 percent—not because of who you are, but because of what you don’t eat. It did not matter what type of cognitive ability we looked at, malnutrition had an influence on verbal IQ as well as spatial (nonverbal) IQ.
In Mauritius, as in my day at primary school, they take national examinations at age eleven to decide what type of secondary school they will go to. The exams are in English, French, mathematics, and environmental studies. It really decides the rest of these children’s lives. We looked at their performance on these standardized national examinations, and again we found that poor nutrition drives down academic scores in a dose-response fashion. The same thing with neuropsychological test functioning at age eleven, and the same thing with reading ability. Poor nutrition sinks school performance and neurocognitive functioning. And yes, we know that poverty and parental education is linked to both IQ and poor nutrition, but controlling for multiple social adversity indicators like these did not alter the relationship. We could not escape the fact that nutrition is in its own right absolutely critical for kids to do well in all realms of intellectual life, and has real-life consequences in determining what level of secondary education the kids end up getting.
From nutrition to cognitive functioning and back to behavior problems. We are on our way to a part-answer to the core question of “What is the mechanism of action?” Does poor nutrition make a dent in cognitive functioning? And do dull wits turn kids to vandalism and antisocial activities? It seems that they do. Liu statistically controlled for the fact that kids with poor nutrition have lower IQ.15 This technique makes the good and poor nutrition groups equal on intelligence. When that is done, the group difference in antisocial behavior disappears. This vanishing trick identifies poor cognition as a likely mechanism. Poor nutrition leads to low IQ, and this lowering of cognitive ability leads to antisocial behavior.
And it makes sense. You can imagine how low IQ can lead to school failure. You likely did well in school, but imagine what it’s like to instead go in every day and get stuck on your reading, get your mind numbed with numbers that don’t add up, while all the time most other kids seem to be doing just fine. Day in, day out, you’re a failure. A failure for weeks, for months, for years.
It’s easy to see how this can result in low self-esteem and a loss of hope. No wonder such kids try to bail out and kick back against the institutional system once they gain the muscle to rebel. Note here that just because poor nutrition acts negatively on the brain to predispose someone to aggression, we are not saying no to social factors altogether. Indeed, poor nutrition is very much an environmental factor. We see here that a negative environment—not getting enough of the right food—results in poor brain and cognitive functioning, which leads some kids down the primrose path to crime and violence. And as we are about to see, it’s something of a slippery slope.
Strange stories abound when it comes to trying to explain violence and other devious behavior. Perhaps one of the strangest circulating at the moment is that it’s all to do with how much fish we eat. This may sound odd, but if we take a close look at the data, what your grandma always told you may be literally true—that fish food is brain food. And if something affects the brain, it’s up for grabs as a causal agent in crime.
We’ll begin with a topic in criminology that does not receive as much attention as it should. Why do countries around the world differ so much in violence, and what’s the cause of these differences? There are plenty of ideas, old and new. Differences in unemployment rates do not seem to explain international differences in homicide and, perhaps surprisingly, neither does urbanization.16 A lot of emphasis has been placed on social processes and for good reason, as the correlational data supports it. As we might expect, gross domestic product (GDP) is a strong correlate—the lower the GDP, the higher the violence: a correlation of .68. It really makes sense if we think of poverty as a cause of crime, because a higher GDP goes along with political development, increased democracy, and better education of the people.
A different social mechanism—income inequality—endorses this social perspective. As measured by the Gini index, the higher the income inequality, the higher the homicide rate—a correlation of .57. So the more a country is divided into the haves and the have-nots, the higher the homicide rate. Denmark, Norway, Sweden, and Japan all have relative income equality and low homicide, while countries like Colombia, Botswana, and South Africa have high inequality and high homicide, with the United States in between on both counts.
Interestingly, psychological beliefs also play a role. Some people prefer money, while others prefer love. What would your own pick be? We all differ to some degree, and just like individuals, countries as a whole differ from each other in the relative value they place on love, on the one hand, versus social status, good financial prospects, power, and status on the other. In countries where people believe love is more important than money, there is less violence. Perhaps the Beatles were not far off the mark—all you need is love.
But we need to eat as well as make love. And this is the fishy part. Countries differ an enormous amount in how much fish they eat, just as they differ in their homicide rates. Joe Hibbeln, a leading fish-oil expert working at the National Institute on Alcohol Abuse and Alcoholism in the United States put yearly homicide rates and fish consumption together. He found that they were negatively related—at a correlation level of -.63.17 Take a look at Figure 7.3. It does look as if something may be going on here. Take Japan. They have very low yearly homicide rates—only one homicide per 100,000 people—and they eat well over their own body weight in fish every year. Then you look at eastern European countries like Bulgaria. They eat a measly four pounds of fish a year and rack up homicide rates ten times that of Japan. If you pick out the East Asian countries, they almost follow a straight line, with China at 4.3 homicides/100,000; Singapore at 3.8; South Korea at 3.0; and Japan at 1.2. The greater the fish consumption, the lower the homicide rate.
Figure 7.3 Relationship between seafood consumption and homicide rates across the world
I showed Joe Hibbeln’s provocative data in a talk I gave to the Criminology Department at the University of Pennsylvania in 2005 when I was being interviewed for a job, and one provocative question posed was, “Wait a bit, where’s America here?” The United States was not on the graph of twenty-six countries. My colleagues-to-be didn’t exactly smell a rat, but felt it was a bit of a slippery story. So they went and looked up the data for the United States for the year in question, and what did they find? Fish consumption right in between the two least-fish-consuming countries, Hungary and Bulgaria, and with homicide rates way up at 9 per 100,000, right next door to the eastern European countries. The correlation of -.63 was large and just as strong as that between GDP and homicide rates.
Explaining differences in violence across countries in the world is one thing, but such explanations may or may not apply to variations in offending within a country. Yet even within countries there is evidence that variation in fish consumption is related to antisocial behavior. In a very large sample—11,875 pregnant women from Bristol, England—women who ate more fish during pregnancy had offspring who showed significantly higher levels of prosocial behavior at age seven.18 Put another way, the offspring of mothers who did not eat much fish during pregnancy had more antisocial behavior.
In the United States, a study of 3,581 people from Chicago, Minneapolis, and Birmingham, Alabama, showed that those who hardly ever ate fish had higher levels of hostility than those eating fish at least once a week.19 There are also more behavior problems and temper tantrums in boys with lower total fatty-acid concentrations as measured from blood.20 The same is true of aggressive cocaine addicts.21 Even dogs with low levels of omega-3 have been shown to be more aggressive.22 Giving your dog omega-3 may do more than give it a sleek, shiny coat.
Let’s just suppose for a minute that this is a causal relationship, that bolting down boatloads of sushi and salmon somehow stops you from blowing your fuse. How on earth could this be possible from a scientific standpoint?
There is a reasonable answer based on experimental studies that manipulate the amount of omega-3 that rats have in their diet.23 Recall from previous chapters that violent offenders have brain structural and functional impairments as well as neurochemical deficiencies. Fish is inevitably rich in fish oil. Fish oil, in turn, is rich in omega-3—a polyunsaturated long-chain fatty acid. Omega-3 has two important components—DHA (docosahexaenoic acid) and EPA (eicosapentaenoic acid). What does DHA do? It is known to play a key role in neuronal structure and function. Making up 6 percent of the dry cerebral cortex, it influences the functioning of the blood-brain barrier that regulates what gets into your brain from your bloodstream. It enhances synaptic functioning, facilitating communication between brain cells. It makes up 30 percent of the membrane of your brain cell and regulates the activity of membrane enzymes. It protects the neuron from cell death. It increases the size of the cell.
DHA also stimulates neurite outgrowth. There is more intricate dendritic branching in the neurons of animals fed a diet rich in omega-3 compared with those fed a normal diet. Dendrites of the cell receive signals from other brain cells, so this dendritic branching translates to more connectedness between cells. The axon that transmits the electrical signal to other cells is longer and has a better sheath to conduct the electrical impulse. DHA regulates serotonin and dopamine neurotransmitters, and we saw in chapter 2 that offenders have abnormalities in those neurotransmitters. We also know that DHA is involved in regulating gene expression,24 so in theory it can help turn on genes that protect against violence—or turn off genes that increase the probability of violence.
We also saw earlier that cognitive functioning is impaired in offenders. Omega-3 supplementation has been shown to improve learning and memory in animals,25 and also improves learning in children.26 So it’s not just that omega-3 in theory improves the brain. In practice, it makes a difference in terms of cognitive functioning—and cognitive functioning is critical for performance in school and success in life.
Omega-3 enhances both brain structure and function. We saw in earlier chapters that brain structure and function is impaired in offenders. So it’s perhaps not all that surprising that we find associations between the amount of fish consumed and the perpetration of violence.
You might still find this all a bit too much to believe. Surely it can’t be that simple? And correlation is not necessarily causation, right? You’re correct on both counts. But what we will see in a later chapter on treatment is that there is mounting evidence from randomized controlled trials that omega-3 is effective in reducing antisocial behavior—and such trials are as good as it gets in establishing causality and demonstrating a true and meaningful relationship.
But you’re likely still not convinced, are you? What use are these malnutrition studies to the United States, or other prosperous nations? Look around, everyone seems pretty healthy and there’s plenty to eat. These results must be a problem only in developing countries, like Mauritius.
And you’ve got a reasonable point here. Visitors to the United States cannot help but be struck by the abundance of food and the big portions that are served up in basic restaurants. And the desserts are veritable mountains of yumminess. You take a look around you and, well, people do look kinda big in America. Rates of obesity are 30.6 percent for the United States and 23.0 percent for the United Kingdom, compared with 12.9 percent for Germany, 10.0 percent for the Netherlands, and 3.2 percent for both South Korea and Japan.27 There’s certainly no lack of sustenance over here in the United States, so what’s the deal with all the violence?
There are three complementary perspectives to this issue. First, if you meet or see pictures of adult murderers, it’s true that they certainly don’t look malnourished. But this belies the fact that as children some of them, like the killers Henry Lee Lucas and Donta Page, were surviving by rummaging around in garbage cans. Page was an unfed, malnourished, scrawny little boy when he was growing up in the ghettos around Washington, D.C. But when as an adult he raped and killed Peyton Tuthill he weighed in at over 300 pounds. The outer appearances of adult offenders can be very misleading, hiding years of malnutrition at a critical early juncture in life when the brain is rapidly developing.
Second, there are two types of nutrients—macronutrients and micronutrients. Kids in America are getting plenty of the macronutrients—carbohydrates, fat, and protein.28 But the story is different for the second component—the micronutrients that include vitamins and trace minerals, things like iron and zinc. They are “micro” because the amounts we need every day are really small, in the order of micrograms or milligrams. Yet they are critical for the growth and maintenance of body and brain functions. At the level of micronutrients, the World Health Organization argues that up to one half of all the children in the world have iron or zinc deficiency.29 That’s a staggering fact.
Third, we’ve also got to factor in that there is a wide range in the “bioavailability” of nutrients—the ability of the nutrient in question to get into your bloodstream and act on your brain. Bioavailability is influenced both by a host of genetic factors that determine how well nutrients are absorbed from the gastrointestinal tract, and also by environmental factors such as food inhibitors and enhancers. So, essentially, you can have two people with the same intake of micronutrients, but they may differ radically in terms of the degree to which those micronutrients get into their bloodstreams and act on their brains.
Once again, outside appearances and how well-fed a person appears to be can be very deceiving. Big is not better when it comes to body size and nutrition. Genes and environment, the two big gladiator arenas in which we have been seeing violence played out, can also starve the brain of critical nutrients. Given their potential importance, let’s take a brief look at these micronutrients and the roles they may play in violence.
What are micronutrients? They include vitamins as well as important trace minerals like iron and zinc. If as a kid you had acne or if you had white spots on your fingernails, as I did, you can suspect zinc deficiency.
Deprive mice of zinc and their aggression increases threefold.30 Even before birth, zinc deprivation during pregnancy in rats increases their offspring’s aggression.31 Children and adults in the United States with assaultive and aggressive behavior have abnormally low levels of zinc relative to copper.32 A Turkish study similarly found that violent schizophrenics had lower zinc and copper ratios than nonviolent schizophrenics.33
Iron is another important micronutrient. Several studies have found aggressive and conduct-disordered children to be zinc-deficient.34 One study found iron deficiency in a third of juvenile delinquents.35 Preschoolers with low iron also show a reduction in positive emotions.36 This is significant because a lack of positive emotion characterizes conduct-disordered children.37
Let’s link back to the brain again to understand why these micronutrient deficiencies can predispose someone to violence. Micronutrients like iron and zinc are critical for the production of neurotransmitters and are important for brain and cognitive development. If you reduce dietary levels of zinc and protein in rats during pregnancy, then their offspring show impaired brain development.38 Adult animals fed a zinc-deficient diet show “passive avoidance learning deficits.”39 This is an inability to learn to inhibit a response that leads to punishment, a cognitive deficit repeatedly found in offenders who have difficulty learning from their mistakes.40
We can also link micronutrients to specific brain structures involved in violence. The amygdala and hippocampus, which are impaired in offenders, are packed with zinc-containing neurons. Zinc deficiency in humans during pregnancy can in turn impair DNA, RNA, and protein synthesis during brain development—the building blocks of brain chemistry—and may result in very early brain abnormalities.41 Zinc also plays a role in building up fatty acids, which, as we have seen, are critical for brain structure and function.42 The availability of iron in the brain, like zinc, has been shown to affect neurotransmitter production and function.
What results in iron and zinc deficiency? It could be a lack of foods like fish, beans, and vegetables. Bear in mind that micronutrients play an important role in fetal brain development, and up to 30 percent of pregnant mothers with low socioeconomic status are believed to be iron-deficient. Smoking during pregnancy also impairs the transportation of zinc from the mother to her fetus,43 depriving the fetal brain of a key nutrient. We have already seen that smoking during pregnancy predisposes a woman’s offspring to adult violence.
Amino acids are also important because they are what proteins are made out of. Eight of our twenty-two amino acids are essential because our bodies cannot produce them. Animals fed diets reduced in one of these—tryptophan—become aggressive, while high-tryptophan food reduces their aggressive behavior.44 When tryptophan is experimentally reduced in men and women,45 they respond more aggressively when provoked.46 Reversing that scenario, when tryptophan is enhanced, aggressive behavior is reduced.47
Low tryptophan likely increases aggression because it impairs the brain’s ability to inhibit responses that we should not make. Brain-imaging research has shown that reducing tryptophan reduces functioning in the orbital and inferior regions of the right prefrontal cortex when subjects try to refrain from making a response to a stimulus.48 We saw earlier that this underneath part of the prefrontal cortex is functionally and structurally impaired in offenders. Because serotonin is synthesized from tryptophan, the amino acid likely predisposes someone to reactive aggression by lowering brain serotonin, the neurotransmitter we saw in chapter 2 to be depleted in impulsive violent offenders.
Where does tryptophan come from? Foods like spinach, fish, and turkey. We see that omega-3 from fish could have a calming effect on aggression. In addition to fish, you might also tell your kids to eat their spinach—even if Popeye is not exactly the best role model for nonaggressive behavior.
Sugar rush. Many of us have experienced it. We eat a ton of high-carbohydrate foods and drinks and then feel an energy rush that can make us feel able to shoot for the stars. Then we can feel a little agitated, get light-headed and on edge, and make a crash landing. That’s what was claimed when Dan White killed the mayor of San Francisco, George Moscone, along with the city supervisor and gay-rights activist Harvey Milk.
Dan White was down in the dumps. Life wasn’t working out too well. Having gone from serving in the Vietnam War to working as a police officer and then as a firefighter, he was familiar with high-risk life adventures. But his latest risky venture, a potato restaurant, wasn’t working well, and he was out of money. He had resigned his position on the San Francisco Board of Supervisors—a position he had gained with strong union support from both firefighters and the police.
He had also fallen out with Harvey Milk, who was supporting the establishment of a juvenile detention center that had been proposed by the Catholic Church and was located in White’s district. Now, while Dan White was a Roman Catholic, he was dead set against having the detention center in his district. He also had a gripe with gays, and Harvey Milk was gay. White had resigned from his political position to focus on his potatoes, but with their failure he went back to Mayor Moscone to regain his position. Moscone was in favor, but Milk was against White’s reappointment.
In a fit of reactive aggression, White took a gun and entered San Francisco City Hall through a window to avoid the metal detectors. He went into Mayor Moscone’s office and begged him to restore his position. Moscone refused, so White shot him dead. He then went into Harvey Milk’s office and shot him dead too.
Enter the Twinkie. At his trial, White’s defense team and their psychiatrists argued that he was suffering from depression and had immersed himself in an orgy of junk foods and drinks packed with refined sugar. Bad diet could influence his mood. White was a white working-class heterosexual all-American Catholic who had fought for his country and once saved a woman and her baby from a fire. The jury was made up of predominantly white working-class people who shared White’s values. Some openly wept when they heard the pressure he was up against in his life. Instead of first-degree murder and the death penalty, he was found guilty of voluntary manslaughter and received a prison sentence of seven years and eight months.
The San Francisco gay community went nuts. Even Acting Mayor Dianne Feinstein proclaimed: “Dan White has gotten away with murder. It’s as simple as that.”49
White’s defense had been buttressed by $10,000 that the police had raised for him. The result was the “White Night Riots.”50 A crowd of 1,500 quickly gathered that night in the predominantly gay Castro District, where Milk had lived. It grew to an ugly 3,000 who descended onto City Hall and tore the place apart.51 Police cars were set on fire. After establishing order at City Hall, police retaliated by going into bars in the Castro area and beating up gays. Sixty-one police officers and over a hundred gays were hospitalized for injuries. Dan White eventually committed suicide.
All this because of a little Twinkie?
Not quite, but near enough. Twinkies themselves—sponge cakes with cream filling—were never actually brought up at Dan White’s trial, and the term “Twinkie Defense” was a phrase invented by the press. But junk food was brought up at the trial. Could it really contribute to diminished rational thought, as the defense argued? The claim certainly caught on rapidly after the trial. As one protestor put it to reporters as he was setting fire to a police car on that White Night, “Make sure you put in the paper that I ate too many Twinkies.”52
White’s behavior may or may not have been influenced by junk food, and even if it did contribute to the homicides, we are hard-pressed to view this as an excuse—either an excuse for Dan White’s outrageous actions or, indeed, an excuse for the reactions of the local community. But if there is a mechanism at play here with respect to aggression, the likely candidate is refined carbohydrates. A number of studies have claimed that dietary changes aimed at reducing sugar consumption reduce institutional antisocial behavior in juvenile offenders. Some of these claims are striking. For example, one early controversial study—a two-year double-blind controlled study of twelve- to eighteen-year-old delinquents—obtained a 48 percent reduction in disciplinary offenses after diets were altered in order to reduce refined carbohydrates.53 Experimental studies in animals have also demonstrated a causal relationship between low blood sugar and aggression in rats.54
Let’s move on to Peru and the Quolla Indians for another course in the recipe for violence. The Quolla have a very high rate of homicide and incessantly feud with each other, and have been called, a bit harshly, “perhaps the meanest and most unlikeable people on earth.”55 One anthropologist who studied them made the keen observation that a significant number of their acts of aggression seemed to be without good cause.56 He also noticed that the Quolla were often hungry and craved sugar. Could it be that their irrational aggression was due to low blood-sugar levels and reactive hypoglycemia? A glucose-tolerance test, which assesses propensity for low blood-sugar levels, confirmed a relationship between low blood sugar and both physical and verbal aggression in the Quolla.57 When you next feel irritable and angry for reasons that are not obviously apparent, you might consider a quick nutritious nibble to restore your sugar levels—but not a Twinkie.
In Finland, Matti Virkkunen, who is a psychiatrist at Helsinki University, has been repeatedly demonstrating in some important studies very significant metabolic abnormalities in violent offenders that fit the low-blood-glucose idea. In a series of early studies, Matti demonstrated that violent offenders were more prone to hypoglycemia. He demonstrated that aggressive psychopaths had increased insulin secretion, which would explain their low blood-sugar levels.58 More recently, Matti found low glucose metabolism and low levels of the hormone glucagon in another group of violent Finns.59 He then found that low glucose and glycogen formation predicted which violent offenders would go on to commit further violence eight years later, with the two measures explaining 27 percent of this future recidivism.60
If Matti Virkkunen and others are right, how exactly would the recipe of junk food, hypoglycemia, and low glucose metabolism push a person to violence and aggression? It goes something like this. Diets high in refined carbohydrates can cause extreme fluctuations in blood glucose levels—foods like white bread and white rice. Such foods have the bran, germ, and nutrients stripped from the whole grain, taking away the fiber. Because of the fiber loss, they are rapidly absorbed by the gut, resulting in a large and rapid increase of glucose swishing around in the bloodstream. This in turn triggers an inappropriately large secretion of insulin. Insulin’s job is to soak up the excess glucose and convert it into glycogen so that surplus energy can be stored for future use. But too much insulin release results in too much of the available glucose being taken out of circulation. This is bad news for the brain, which requires at least 80 milligrams of glucose a minute to function efficiently. Drop below that mark and you progressively observe symptoms of nervousness and irritability. That combo of increased irritability combined with feeling on edge could be the first step in the development of a full-blown aggressive outburst. It’s not too surprising, therefore, that when glucose levels of subjects are experimentally lowered in the laboratory, people report feeling more angry even though there is no provocative stimulus.61
But what’s really shocking is a recent study by Stephanie van Goozen and her colleagues at Cardiff University in Wales that was conducted on a sample of 17,415 British babies born in 1970.62 When they were ten years old, the children were asked how often they ate sweets. Van Goozen showed that the kids who ate sweets every day were three times more likely to become violent by age thirty-four. They controlled for many factors, and the results remained significant.
If this relationship is causal, what’s going on? It could be reactive hypoglycemia. The kids who are helping themselves to candy at age ten are also helping themselves to a lifestyle of unhealthy eating habits—high-energy, highly refined carbohydrates that result in too much sugar too quickly. The resulting rebound of very low blood sugar and symptoms of irritability can predispose a kid to giving someone else a good punch in the face in the school playground. Or, as an adult, a broken bar glass in the face. Keep your kids off the candies.
If you think sweets are bad for you, they’re nothing compared with other things that can get inside you, mess up your brain, and make you flex your muscles. I’ll suggest here that heavy metals can form some of the ingredients in the concoction for crime causation. Let’s take a look at a few of the key ingredients.
We saw in chapters 3 and 5 that the structure and function of the brains of violent offenders—especially the prefrontal cortex—is compromised. We have also hypothesized that these brain impairments produce secondary effects—emotional, cognitive, and behavioral—which in turn shape violence. Lead is a leading candidate as a source of these structural and functional brain impairments.
First and foremost, lead is neurotoxic, meaning that it kills neurons and damages the central nervous system. The neurotoxic effects of lead have been known for millennia, and efforts to reduce it are not recent. They have a connection to my favorite drink in England—cider. Back in the seventeenth and eighteenth centuries there was a common malady known as Devon colic, a neurological condition that particularly afflicted people in the southwest of England. They grow a lot of apples down in Devon and cider was almost a staple drink there back then. It was thought that the acidic apple juice caused the colic. Yet in the late eighteenth century George Baker, a physician, identified the cause as lead contained in the cider presses. Over the next few decades lead was steadily taken out of the presses. A near-miraculous reduction in Devon colic occurred, proving Baker’s hypothesis.
Lead’s neurotoxic effects are documented in brain-imaging studies of workers exposed to the metal in their jobs. One study scanned the brains of 532 adult men who had worked in a lead chemical plant.63 There was a wide range of bone-lead levels in these participants, but an average reading was at the very top of the safety level.64 Workers with relatively high bone-lead levels had smaller volumes of many brain areas even after controlling for multiple confounds like age and education levels. The fact that the frontal cortex was particularly reduced65 is very interesting, given that this brain region is involved in violence. This lead effect was equivalent to five years of premature aging of the brain.
So lead workers have brain volume reductions. What about people in the community like you and me who likely have just low to moderate levels of lead in our blood? This question was addressed in a study of 157 individuals from Cincinnati who had had their blood-lead levels measured twenty-three times from the ages of six months to six and a half years.66 This prospective study again showed that those with high lead levels had low brain volumes. One of the brain regions most affected was the ventrolateral prefrontal cortex, that lower outer region of the front of the brain that is impaired in antisocial and psychopathic individuals. This community sample had an average blood-lead level at age six that was high, but still within the so-called “safe” range as defined by the Centers for Disease Control and Prevention. We can see, then, that those exposed to “safe” levels of lead can suffer from brain impairments. Furthermore, the prospective nature of the study, moving from childhood lead exposure before age six to brain structure at age twenty-three, helps to establish causality.67
These studies give clear documentation of the negative impact of lead on the brain, and, intriguingly, they also document that the brain area most frequently found to be compromised in violent populations—the frontal cortex—is particularly impacted by lead exposure. The next question is whether those with high lead levels are found to be more antisocial.
The landmark study in this area was conducted by Herbert Needleman at the University of Pittsburgh. He found that boys with high lead levels have higher teacher ratings of delinquent and aggressive behavior, and also higher self-reported delinquency scores. It was an impressive and influential study. Similar links have been found in at least six other studies in several different countries.68 Furthermore, experimental exposure to lead during development increases aggressive behavior in hamsters, thus suggesting a causal link.69
Environmental lead exposure, therefore, is a risk factor for antisocial and aggressive behavior in delinquent kids. What about adult crime? And how early in life does this association occur? Answers to these questions were obtained in a methodologically strong study of African-American pregnant women.70 Both prenatal and postnatal blood-lead levels in their offspring dramatically predicted adult crime in the early twenties and also adult violence. For every 5 microgram increase in prenatal blood-lead levels, there was a 40 percent increase in the risk for arrest.71 Given that a 5 microgram increase from birth to age five still keeps you well below the limits of what the Centers for Disease Control and Prevention considers safe, this constitutes substantial risk from just a moderate, “safe” amount of lead exposure.
The last study shows that blood lead very early in life is an important predictor of adult crime. We also know that blood-lead levels are maximal at twenty-one months, when children are most exposed to lead.72 Why is that? You know that toddlers put their fingers in their mouths a lot. And they also get their fingers into every pie they can, including mud pie outside in the garden. Lead lingers well after its release into the environment and stays in the soil for years. Even though gas is now unleaded, the lead residue from the past still lingers in the soil, especially near major roads and freeways.
High blood-lead levels later in childhood can be even more important. One study in Yugoslavia73 recruited pregnant mothers in 1992, just at the time of the large-scale ethnic conflict between the Serbs and the Croats. The mothers came from two towns near lead smelters. Blood-lead levels in their offspring at age three were more strongly related to destructive behavior than the prenatal measures of blood lead. Similar findings have been obtained in America, with high blood lead at age seven—but not age two—correlating with high antisocial and aggressive behavior at age seven.74 So lead exposure still matters well after the age of twenty-one months.
Lead research lends itself to an intriguing conceptual point. What has puzzled criminologists is the unpredicted drop since 1993 in violence after a continuous rise, which flew in the face of criminological predictions of further increases. For example, within seven years violent crime in New York had dropped 75 percent. Many sociopolitical explanations were given, but none could account for both the rise and the fall in crime across several decades. Critics of neurocriminology argue that biology cannot, of course, explain differences in violence over time or across regions within a country. Isn’t biology fixed and static? Surely it cannot explain secular trends—shifts in violent crime rates across time.
But it can, and dramatically so. In research papers buried in an obscure environmental journal, Rick Nevin documented a strikingly strong relationship between changes in environmental lead levels from 1941 to 1986, and corresponding changes in violent crime twenty-three years later in the United States.75 So, young children who are most vulnerable to lead absorption go on twenty-three years later to perpetrate adult violence. As lead levels rose throughout the 1950s, 1960s, and 1970s, so too did violence correspondingly rise in the 1970s, 1980s and 1990s. When lead levels fell in the late 1970s and early 1980s, so too did violence fall in the 1990s and the first decade of the twenty-first century. Changes in lead levels explained a full 91 percent of the variance in violent offending—an extremely strong relationship.
Nevin found exactly the same matching of the lead levels and violence curves in Britain, Canada, France, Australia, Finland, Italy, West Germany, and New Zealand.76 There was cross-cultural replication. Furthermore, in states where lead levels dropped more quickly, later violent crime also dropped more quickly.77 Variations in lead levels even correlate with variations in crime rates within cities.78 From international to national to state to city levels, the lead levels and violence curves match up almost exactly.
Kevin Drum, a political blogger and columnist argues that these findings have been completely ignored by criminologists. He contacted criminology experts and none of them showed a scrap of interest.79 Why? Likely because to recognize that secular trends and both rises and falls in violence can be partly attributed to brain dysfunction—and not to better policing or to gun control or to the end of the crack epidemic —would be to recognize the explanatory power of biology theories. Currently that’s something very difficult for many social scientists to accept.
At a McDonald’s next to the post office in the community of San Ysidro, near San Diego, at 3:40 p.m., on July 18, 1984, a middle-aged man walked in with a 9-millimeter semiautomatic Uzi and unloaded 257 rounds of ammunition into the customers. The shooter, James Oliver Huberty, killed twenty-one people and wounded nineteen others.80 His victims ran the gamut in age from just seven months to seventy-four years.
What on earth made Huberty do it? Cadmium is a very likely culprit. An analysis was made of Hubert’s hair after he was shot dead by a SWAT team sniper perched on the roof of the next-door post office. The results were nothing short of astonishing. In the words of William Walsh, the chemical engineer conducting the analysis, “He had the highest cadmium level we have ever seen in a human being.”81 Huberty’s lead levels were also high, so he had a double hit. There’s no mystery as to why he had multiple metals in his body. Huberty had been a welder for Union Metal for a number of years until he gave it up. The reason he left his welding position? In an exit interview that he gave to his employer upon leaving, he said, “The fumes are making me crazy.”82
So cadmium can be a killer, not just in people like Huberty, and not just in the United States. Certainly, hair samples from violent offenders in the U.S. show them to have more cadmium than nonviolent offenders.83, 84, 85, 86 High hair-cadmium levels also characterize U.S. elementary schoolchildren with behavioral problems.87 The same is true for schoolchildren in China, a leading producer of cadmium. The Dabaoshan mine in the city of Shaoguan in the Guangdong province is a multi-metal mine. Water is used to leach the ore, and the waste water is then transported by rivers to local villages, delivering a large dose of heavy metal to the villagers. The result is that the crop region in this countryside has sixteen times the recommended level of cadmium. A study of schoolchildren living downstream from the mine showed that hair-cadmium levels explain 13 percent of the variation in their aggressive and delinquent behavior.88 Cadmium is quite a heavy-metal key on the biological key chain unlocking the etiology of violence.
It’s not hard to see how people living near a mine are exposed to cadmium, but what about the rest of us? Not surprisingly, cadmium is a hazardous substance that can cause death and is banned by the European Union for use in electrical equipment. Yet about 75 percent of all cadmium in the United States is used in rechargeable nickel-cadmium batteries rolling around your home right now. Not too harmful there, perhaps, but cadmium does find its way into the environment from municipal waste grounds and fossil fuels because products containing cadmium are rarely recycled.
The people most susceptible to cadmium? Smokers. They inhale about 10 percent of the cadmium content of a cigarette, which gets nicely absorbed into the bloodstream from the lungs.89 They end up with five times the cadmium levels of nonsmokers.90 The rest of us get exposed too, because foods like offal (the internal organs of animals) and cereals91 account for 98 percent of our cadmium intake. In contrast, seafood, which we saw earlier to be associated with lower violence, accounts for only 1 percent.92
The twist here is that the amount of cadmium acting on your body is a function of other factors. Iron blocks the intestinal absorption of cadmium.93 Women on vegetarian diets have reduced iron levels and they also have increased cadmium exposure. If they smoke as well they will have an exponential increase in cadmium. This may partly explain why low iron is associated with violence—individuals with low iron levels are more susceptible to the negative effects of cadmium on the brain.
Everett “Red” Hodges is one of those larger-than-life characters whose charismatic and witty stories blend with forceful argumentation to make you believe almost everything he has to say. His sons have been both perpetrators and victims of crime. One was a rebel without a cause who got into a load of trouble as a juvenile delinquent. The other was mugged in a parking lot and very badly beaten up, suffering brain damage as a result. “My son was damn-near murdered,” Red said in an interview. “I know the anguish and suffering that families go through. And you can’t put a price on it.”94
Red reasoned that if the criminal justice system had done a better job of dealing with the neurobiology of violence, his son and many others would never have been the victim of violence. The anguish of many family members would have been spared.
Red pins the blame on one particular metal—manganese. Having made a good deal of money in a Bakersfield oil field in California, Red Hodges sank a million dollars into funding efforts to investigate his hypothesis. Working with Red, Louis Gottschalk at the University of California, Irvine, demonstrated that three different samples of violent criminals had higher levels of manganese in their hair than controls did.95 Roger Masters at Dartmouth University similarly showed that areas in the United States with higher levels of manganese in the air have higher violent-crime rates—even after controlling for multiple socioeconomic confounds.96
At the same time, the manganese debate is a political hot potato, and it’s hard to know who’s right and who’s wrong. Critics reasonably argue that the evidence is mixed and that we cannot easily untangle cause-and-effect relationships from correlational studies.97 What helps here are longitudinal studies involving teeth. The cusp tip of the first molar gives a handle on manganese exposure halfway through pregnancy—a time when a fetus’s brain is rapidly expanding. Using these teeth, researchers showed that kids with high prenatal manganese levels had disinhibited, antisocial behavior across the board on a host of antisocial-behavior measures.98
What causes excessive manganese exposure during pregnancy? A deficiency in iron—the micronutrient that when low is associated with high antisocial behavior—enhances manganese absorption. Women with low iron levels absorb about four times more manganese than women with high iron levels.99 An early postnatal source of manganese is soy infant formula, which has eighty times the amount of manganese that natural breast milk has. It’s possible that the higher IQs found in breast-fed babies may be due to formula-fed babies’ being exposed to high manganese, because manganese excretion is controlled by the liver. The livers of babies are underdeveloped, and consequently they are less able to excrete manganese. The excessive manganese could then result in poorer brain functioning and lower IQs.
Put the two together and you begin to build a recipe for violence. Pregnant mothers have a tendency to have low iron. This will result in increased manganese exposure to the fetuses. Then, when the nippers are born, they get soy milk with a hefty dose of manganese that their little livers cannot deal with. The potential result? One more strike on the brain. Higher manganese levels in children can result in impairments in cognitive speed, short-term memory, and manual dexterity.100 As we noted earlier, this neurocognitive dysfunction predisposes individuals to violence. Furthermore, manganese reduces serotonin, a neurotransmitter that when low causes a predisposition to impulsive violence.
Given this, perhaps it’s not too surprising that fifteen studies on workers exposed to manganese in all corners of the world—including Chile, Great Britain, Egypt, Poland, Brazil, the United States, Scotland, and Canada—without exception report significant mood disruption, including aggression, hostility, irritability, and emotional disturbances.101 In Chile the term used is locura manganica—meaning “manganese madness.” It refers to violence, mood disturbances, and irrational behavior. It’s just the type of craziness that James Huberty reported as the reason for leaving his welding job, this time for another mad metal—cadmium.
It has been documented that the aggressive acts of workers exposed to manganese result in “stupid” crimes that are not premeditated and motivated by gain, but more a result of brain impairment resulting in poor emotion regulation and impulsivity.102 Not surprisingly, low intelligence is an extremely well-replicated risk factor for violent offending, a risk factor that could in part be caused by an excess in manganese.
Moving from manganese to mercury you might expect the same pattern of results to emerge. But they don’t. Mercury is mysterious. Of all the heavy metals, this one may or may not play a role in violence—a fact that is both striking and enlightening. Mercury is toxic to the brain and other body organs, with about half of human-generated mercury coming from coal plants. Dental amalgams are another source, and fish are also argued to be a major dietary contributor.
Despite its toxicity, to my knowledge there are no convincing demonstrations that antisocial and violent individuals have higher mercury levels. It is also surprising that there are so few studies on mercury levels and cognitive ability in community populations. Two major prospective studies that have been done on blood-mercury levels and cognitive-behavioral functioning show conflicting findings.103 One study, conducted in the Faroe Islands, between Scotland and Iceland, found high mercury to be associated with poorer cognitive functioning.104 The other study, in the Seychelles, which is just up the road from Mauritius, in the Indian Ocean, found no association between mercury and cognitive-behavioral outcomes.105 Reviewers are at a loss to explain the discrepancy, putting the difference down to “culture.”106
Yet if we put together a few seemingly unrelated facts, these geographically contradictory findings can make sense. Where do people get mercury from? Supposedly from eating fish that are high up in the food chain—particularly shark, swordfish, and king mackerel, which are certainly on the no-go list for pregnant mothers. In the Faroe Islands they also eat a whole load of pilot whale, especially outside the capital city. What’s the deal with pilot-whale meat? It’s not just very high up in the food chain and high in mercury, but it’s also low on selenium.
Selenium? This is a mineral that defends the brain against “oxidative stress,” a process in which the brain cell takes up too much oxygen, resulting in the production of free radicals that damage DNA and the cell membrane, resulting in cell death. Selenium not only protects against this damage but, more important, it binds with mercury. Like a magnet, selenium latches onto mercury and keeps it from binding with brain tissue, thus preventing brain and cognitive impairment.
If you think about it, fish seem to do okay with all that mercury leaching out of the seabed, and many species are packed with selenium. Going back to the two studies with contrasting results, the high-mercury and low-selenium diet in the Faroe Islands translates into poor cognitive and behavioral functioning. And yet in the Seychelles, pregnant women are also exposed to mercury, eating twelve portions of fish a week. That’s a lot, twelve times the consumption of American women. So what is different in the Seychelles and the Faroe Islands? In the Seychelles they do not eat pilot whale, which is low in selenium. Instead they eat fish high in selenium that buffers them from mercury and its cognitive impairments. Their diet thus protects them against any damaging effects of mercury, as well as providing a high dose of the beneficial omega-3. We shall return to omega-3 in a later chapter when we pose prevention strategies to fight violence.
So we are seeing that biology plays out in the environment and in the physical-health arena when it comes to the makings of malevolence. Some heavy metals take their toll on the brain and predispose people to violence. But health is a multifaceted construct, and it acts in ways other than diet and environmental toxins to shape violence. Let’s not forget mental health. Biological impairments can also make men mad, and madness can make men mean. Women too, perhaps even more than men. Mental illness has its roots in genes and neurotransmitter abnormalities that mess with our minds. And it’s when our minds are mucked up that we are most prone to violence. One prominent and major mental illness that can do this is schizophrenia.
I’ve long had an interest in schizophrenia because it was, in a way, pivotal in moving me out of accountancy and into criminology. Not that I became psychotic adding up all those numbers at British Airways—although at times I did think I was losing my mind somewhere within those cabin-crew accounts. But this clinical disorder did radically change my life. Haven’t we all had those pivotal moments in life when a seemingly chance, inconsequential event changed everything? You pick up some random book, just like you picked up this one, and something clicks. The next thing you know, your life takes a sudden turn—all because of one capricious, unpredictable, and seemingly innocuous experience.
In my case it was a Saturday morning just before lunch in the early summer of 1973, and I was bored to tears working at Heathrow. I knew I’d made a really bad life decision in becoming an accountant, and I was absolutely miserable—had been for months. How had I messed up so badly? I was hungrily hunting for some books at a bookstore in Hounslow where I lived to read over my Saturday lunch treat—an “American” cinnamon apple pie and ice cream—and it leaped out at me. A slim paperback by R. D. Laing and Aaron Esterson entitled Sanity, Madness, and the Family.107 Laing’s riveting collection of eleven case studies of schizophrenic patients challenged the prevailing medical model that schizophrenia was a brain-based disorder. Instead this existential psychiatrist argued that schizophrenia had an environmental basis stemming from faulty communication within the family. Schizophrenics have outrageous and bizarre beliefs, but their madness becomes understandable when we consider the context of the family.
I had an epiphany. It was all making sense. So that’s how I ended up as such an oddball—it was all my nutty parents! It was a revelation that made me determined to understand myself more and to study psychiatry (I ended up studying psychology instead), to challenge the biological model of mental disorder (I eventually did the opposite), and to work in hospitals helping schizophrenic patients (trade that for four years in prison helping psychopaths). Books change our mind-set and sometimes our life—though not always in the way we anticipate, and not necessarily in the right way.
Laing and Esterson weren’t exactly right either. Schizophrenia turns out not to be caused by faulty parent-child communication patterns but is instead a debilitating, brain-based, neurodevelopmental disorder characterized by delusions, hallucinations, thought disorder, lack of emotion, and disorganized behavior. Affecting about 1 percent of the population around the world, it frequently hits women in their early twenties and men in late adolescence, with about 40 percent of male schizophrenia cases occurring before the age of nineteen—an intriguing fact given that these late adolescent years are also the peak age for violence in men.108
What’s also intriguing is that when we look at the biological factors that are related to schizophrenia, we find many of the same risk factors that we have seen earlier characterizing violence. Things like frontal-lobe dysfunction, neurocognitive impairment, fetal maldevelopment, birth complications, blunted brain responses to stimuli we should normally pay attention to, and orienting abnormalities. To be sure, crime and schizophrenia are certainly not the same condition. They present very differently to the clinician. And there are risk factors like low resting heart rate that are unique to crime and unrelated to schizophrenia.109 Yet, at some causal level, there is a degree of common ground.
That common ground expresses itself most strongly when we look at the link between violence and schizophrenia. Large-scale epidemiological studies from many countries around the world now attest to the fact that schizophrenia patients are much more likely than normal controls to have a history of violent and criminal behavior. Turning the issue around, delinquent and criminal populations are more likely to show higher rates of psychotic disorders than the general population. This relationship between violence and schizophrenia is not weak. If you are a schizophrenic male, you are three times more likely to kill than someone of the same social background and marital status who is not schizophrenic. If you are a female schizophrenic, you are twenty-two times more likely to kill than a nonschizophrenic female.110
These are striking statistics, and we should be cautious in interpreting them. Many psychiatrists and families of schizophrenic patients do not want to hear this message.111 It’s hard enough for someone with schizophrenia to have to carry the burden of this debilitating illness, let alone to be labeled as violence-prone. It’s true that most schizophrenics are not dangerous and neither kill nor perpetrate violence.112 But the harsh reality is that the neurodevelopmental ravages perpetrated on the brains of schizophrenic patients during childhood and adolescence make them less able to regulate their emotions and hold back their anger as adults.113
You might accept that schizophrenia is a neurobiologically based mental disorder. You may even agree that schizophrenics are more likely than others to kill. But you could counter that schizophrenia is a rare mental illness, so surely it cannot account for much violence. And you’d have a point. What we next need to consider, therefore, is that there is a “watered-down” version of schizophrenia with a higher base rate in the general population.
We have exactly that in a clinical condition called schizotypal personality disorder.114 Instead of hearing voices of nonexistent people, as schizophrenics do, schizotypals mistake an actual noise in the environment for someone speaking. It’s not entirely uncommon. I was in my hotel room at a conference in Tuscany washing and shaving in the bathroom sink when I heard a woman very close by, shrilly saying, “Well, hello.” Startled, I looked around. I looked in the bedroom. Nobody. How peculiar. I went back to washing, and heard the same thing again. It had to be outside in the corridor. I opened the door to my bedroom, but no one was standing out there. This was seeming more bizarre. Going back to washing and turning on the faucet, I realized that the squeaky female voice was none other than the squeaky tap. About every month or so I hear someone calling my name in the street, and look around to find myself mistaken again. Technically, the symptom is called “unusual perceptual experiences”—you mistake sounds for voices and shadows for objects and people. But I’m all right, I tell myself.
Is it just me who’s got a tile loose? Not really. We can measure schizotypal personality quite well using simple self-report questionnaires. I created a measure for it back in 1991 (yes, psychologists really do study the problems they have). It’s called the “Schizotypal Personality Questionnaire.”115 It includes questions like this one: “When you look at a person, or yourself in a mirror, have you ever seen the face change right before your eyes”? We found in Los Angeles that 18 percent of supposedly high-functioning undergraduates said yes to this item. “Have you had experiences with astrology, seeing the future, UFOs ESP, or a sixth sense?” Forty-nine percent say they have. “I feel I have to be on my guard, even with friends” has 21 percent endorsement, while 31 percent agreed that “some people think that I am a very bizarre person.” When we brought in the students whose total score was in the top 10 percent of the undergraduate population for a clinical interview, 55 percent of this group received a clinical diagnosis of schizotypal personality disorder—equivalent to 5.5 percent of the total undergraduate population, much higher than the 1 percent base rate for schizophrenia.
Now, you could put this all down to the fact that it’s L.A. that we’re talking about—a safe haven for loonies from other locations to migrate to so they can fit in with all the other nutters and not seem so obviously bananas. And there might just be a smidgen of truth to that West Coast stereotype. But at the same time, the reality is that psychosis has its manifestation at a dimensional level. There are shades of gray here, and there is a surprisingly large minority of people in the population with some characteristics similar to schizophrenia.
Are these individuals more likely to be violent and antisocial? Yes, they are. Whether we look at undergraduates at universities—the privileged offenders—or just individuals in the community, those with higher scores on the “Schizotypal Personality Questionnaire” have higher scores on self-reported measures of crime and violence.116 They parallel what many others find in clinical populations of schizophrenics. Put together those with schizotypal personality and those with outright schizophrenia and other psychoses, and you really do have a small but significant group at risk for crime and violence.
But why would schizophrenics be more likely to kill than others? One answer can be found at the surface level in the symptoms of schizophrenia. For one thing, one common manifestation of schizophrenia is paranoia. Paranoid schizophrenics are overly suspicious of other people’s intentions, and believe others are out to get them. If you believe that, then one reasonable defense is to get them before they get you. Other schizophrenics have delusions of grandeur, which can give them a righteous sense of power and control over others, or a religious grandiosity that may make them feel they have the right to override the sanctity of life. Other schizophrenics have a messianic vision—they are a prophet come to save the world from its debauchery and sins. One way of doing this, of course, is to kill as many prostitutes as you can, just as we saw with Peter Sutcliffe.
There are also features common to schizotypals and psychopaths. These two disorders may seem like chalk and cheese on the surface—the shy, retiring schizotypal versus the brash, confident psychopath. But there is a connection. Schizotypals have constricted affect—meaning that their emotions are blunted and reduced. We similarly see in the research literature on psychopaths repeated evidence of this emotional blunting. They just do not experience emotions in the same way that the rest of us do. Schizotypals also have no close friends outside of their family members, and in a similar fashion psychopaths form only very superficial, fleeting relationships, having an inability to form the deep and meaningful social affiliations that the rest of us do.
These superficial similarities partly explain why schizophrenics are more violent. In the same way that blunted emotions and a lack of social connectedness with other people nudge the psychopath into the perpetration of violence, social disconnection and a lack of feeling can tip the schizophrenic into violence. And if you can’t bring yourself to imagine some violent offenders as having schizophrenia-spectrum tendencies, then think again. How many serial killers or murderers have you heard of who at some level were extraordinarily bizarre and acted out strange behaviors? Or had a “had to get them before they got to me” paranoid rationalization for their assaults? Or had really odd beliefs about the world and the people in it? Yes, mad murderers are not uncommon. Recall Ted Kaczynski, the mail bomber, and Peter Sutcliffe, the prostitute killer. Crime connects with schizophrenia—at least part of the time.
Plummeting to a deeper level of analysis, another reason for schizophrenics’ being more likely to perpetrate violence lies in the brain. We have known since the 1970s, from the very first brain-imaging studies using CT scans, that schizophrenics have enlarged ventricles—large fluid-filled spaces in the deeper areas of the brain that likely reflect brain atrophy. Since then thousands of brain-imaging studies have documented functional and structural impairments to many brain regions in both schizophrenics and schizotypals, particularly the frontal and temporal lobes.117 These areas are particularly prevalent in violent offenders.118 Recall also in our prior discussion of brain imaging that schizophrenics who commit homicide are especially likely to have structural impairments to these brain areas. Consequently, one possible reason schizophrenics are more violent is that they have structural impairments to those brain areas that regulate aggression, as well as disturbances in the limbic system, where emotion is generated.119
For some schizophrenics, then, it can boil down to an inability to regulate emotion and acting on the spur of the moment. Things just get a bit out of control sometimes. It’s not so much that they meticulously plan an attack or homicide in a cold-hearted fashion. It’s more that their disorganized behavior and prefrontal dysfunction results in more reactive forms of aggression—acting impulsively on a provocative stimulus. Indeed, schizophrenics are more likely to kill their own family members than to kill strangers. As many of us know, the home setting can be a tinderbox where what starts as an off-the-cuff comment becomes an out-of-control, blazing argument. Add paranoia and delusions into the mix, and a spark can become a conflagration.
For kids, that spark may come at school. Together with Annis Fung and Bess Lam at City University in Hong Kong, we found that children with high scores on the child version of the Schizotypal Personality Questionnaire had high scores on reactive aggression.120 In this sample of 3,608 schoolchildren we also found that victimization mediated—or explained—this relationship. Schizotypal kids are picked on because they are odd, shy, and different, and because of that, they reacted by lashing out in anger at others.
The spark igniting the violence tinderbox need not be physical in nature—it might be ideological. Recall from chapter 4 that Ted Kaczynski’s bombings were a reaction to industrialization and perceived scientific control over society. In other cases, homicide can be in reaction to social rejection and a sense of hopelessness. That might have been partly true for Kip Kinkel, who was expelled from Thurston High School and on the same day shot his parents before embarking on a mass school killing. Might social isolation have partly triggered Adam Lanza’s shooting his mother and then later killing schoolchildren at Sandy Hook Elementary School?
Thus, poor mental health is a risk factor for violence in part because it reflects the type of brain dysfunction that can predispose people to violence. We certainly see a lot of evidence of mental-health disturbances in violent offenders. Not just in disorganized murderers overcome by florid symptoms of psychosis, but also in organized serial killers who can exhibit more muted forms of schizophrenia, as well as overt psychotic symptoms. Here’s an example of that muted form and the mix of schizotypal symptoms that include odd beliefs, bizarre behavior, delusional thinking, paranoid ideation, blunted affect, and no close friends.
I doubt any of you have ever heard of Leonard Lake. Though he killed at least twelve—and as many as twenty-five—men, women, and babies, he is still considered a small fry in the bigger sea of serial killers. People like him slip from public attention, where there are so many other killers basking in an eerie limelight. Yet Lake’s case illustrates a mental-health point that is relatively underreported in the literature and needs to be recognized.
Lake had been diagnosed with schizoid personality disorder when he was discharged from the Marine Corps after service in Vietnam. Although he went into psychotherapy, there is no known effective treatment for this personality disorder, one of the schizophrenia-spectrum disorders. Lake was an odd man in many ways. He was fascinated by medieval legends, paganism, and the Vikings. He was once observed to have a large pot on his stove in which he was cooking the head of a goat for soup.121
Odd beliefs and behavior like this are characteristic of those with schizotypal personality disorder. One schizotypal I heard being described at a clinical case conference at UCLA wanted to sleep with a goat. Lake’s behavior and beliefs were no less bizarre. He had delusions of grandeur and developed a vision of running a survivalist compound in which only the strongest and bravest individuals would survive the apocalypse that was about to come. He believed the world would be destroyed in a nuclear war, but that he would rebuild the human race with his collection of young female sex slaves.122
Bizarre beliefs in those with schizophrenia-spectrum disorders don’t pop up from random neural misfiring in the brain. Instead, they have some foundation in the social environment. Lake’s delusions eerily mimic the main theme in Stanley Kubrick’s classic film Dr. Strangelove, which was released in 1964. In the movie, the nuclear-arms race is getting out of control and paranoia is running rampant. Brigadier General Jack Ripper initiates a B-52 nuclear attack against the Russians under the belief that a communist conspiracy lies behind the water fluoridation that is sapping his “precious bodily fluids.” The Russians have, unbeknownst to the West, developed a doomsday device that is programmed to wipe out the world in the event of an attack on Russia. The U.S. president, under the advice of Dr. Strangelove (a former Nazi weapons expert), develops a plan to occupy deep mine shafts. Selected men—who of course would include the president, Dr. Strangelove, and senior officials—will cohabit with many young women selected for their reproductive fitness and attractiveness so that the men may perform prodigious acts of unselfish reproduction to help repopulate the world.
Did Lake once watch Dr. Strangelove, or some similar apocalyptic narrative, and take on board some of these bizarre belief systems? Or were his violent fantasies shaped in part by his tours of duty in the Marine Corps in Vietnam? Or both? Lake certainly had paranoid ideation and believed the wider world was under imminent attack, that it would be wiped out, and that he would need to repopulate the world. He began to act on his beliefs with callous disregard for the suffering of others. He had the cognitive, emotional, and behavioral features of schizotypal personality disorder.
Lake put his vision into operation by setting up a compound in Wilseyville in the rural area of Calaveras County123 in California. There, in his bunker, he stockpiled arms and food to survive the nuclear fallout, complete with all the necessary shackles, chains, and sexual devices to help him repopulate the post-nuclear world. With a partner, Charles Ng, he lured both men and women using classified ads in which he advertised the sale and exchange of video equipment. Men who replied were immediately killed for their possessions. Women were imprisoned in an underground bunker, where Lake and Ng would make them perform sex-slave rituals in snuff videos, begging for mercy as they were tortured and raped.
Schizotypals score lower on empathy than normal individuals,124 and Lake’s level of empathy was decidedly low. He is recorded telling one of his victims, Kathy Allen, “If you don’t do what we tell you, we will tie you to the bed, rape you, shoot you in the head, and take you out and bury you.”125 The reality was to be even worse. Indifferent to the pain he was causing by torturing and raping the women in his bunker, Lake took away the baby of one of his victims, Brenda O’Connor, claiming it was for now in the safe hands of another family. Terrified and hysterical at what might happen to her baby and deluded into believing she could save it, Brenda went along with Lake and Ng’s perverted wishes in their snuff videos. The reality was that her baby had already been cut up and buried outside the bunker, and Brenda was to follow after slow torture with sadomasochistic devices.
As was mentioned above, schizotypals have no close genuine friendships outside of their own families, and while they may have superficial associates, these relationships are not deep and meaningful relationships. Lake’s social connectedness did not even extend as far as his own family. He killed his brother and also killed one of his few associates for his money and possessions, just as he had killed strangers.
A significant number of schizotypals have obsessive-compulsive personality features.126 Lake too had his obsessive-compulsive features, taking several showers a day and repeatedly washing his hands—he was compulsively clean as a child. He also made his victims shower before sex.
Another symptom of schizotypal personality is bizarre behavior. Lake would dissect his victims after murdering them, boil the skin off their bones, and place their remains in plastic bags, which he buried in shallow graves around his bunker. Individuals with schizophrenia-spectrum disorders are at risk for suicide,127 and so it’s not entirely surprising that after being captured Lake swallowed a cyanide pill that he had carefully hidden under the lapel of his shirt. He died four days later.
Leonard Lake was not a schizophrenic hearing voices like Peter Sutcliffe or Ron Kray or Henry Lee Lucas. He did not stand out on the street looking disheveled or talking to himself. Instead, he had the kind of symptoms that are not too obvious or noticeable in isolation, but in unison can be clear signs of someone at risk for violent behavior. Clearly not all people with schizotypal personality are killers—far from it—and there were certainly additional factors that made Lake the monster he evolved into. But I suspect that features of schizotypal personality are far more common in violent offenders than today’s criminal justice system recognizes, largely because these features are not in and of themselves very striking, pathological, or “abnormal.”
After all, did anyone think that Adam Lanza might kill his mother and twenty-six children and adults at Sandy Hook Elementary School in Connecticut in December 2012? At the time of writing—just nineteen days after this tragic event—little definitive is known about his mental condition. Yet to me, he very likely had at the least four of the seven symptoms of schizoid personality disorder: lack of close friends, chooses solitary activities, emotional detachment, and does not desire close relationships or being part of a family. This is the very same diagnosis Leonard Lake was given after his discharge from the Marine Corps. Four out of seven signs are sufficient for a clinical diagnosis. Lanza might also have had the remaining three: takes pleasure in few activities, indifferent to praise or criticism, little interest in sexual experiences. Like Lake, he may also have had additional features of schizotypal personality disorder, including odd appearance/behavior, constricted affect, social anxiety, and odd speech.
I have selected schizophrenia-spectrum disorders from a much wider number of psychological disorders to illustrate that health considerations do not end with physical health. Psychosis and subliminal forms of psychosis—like schizotypal personality—have a strong neurobiological basis and are also clearly related to crime and violence.128
There are two very important caveats to repeat, however. First, most schizophrenics neither kill nor are dangerous to others. We should take care not to stigmatize patients with schizophrenia or schizoid personality as both “mad and bad.” At the same time, we need to recognize the raised rates of violence in schizophrenics so that they can receive treatment to reduce the likelihood of violence, and thus reduce the stigma.129 Second, there are many other mental disorders—including depression, bipolar disorder, ADHD, and borderline personality disorder—that are also significant mental-health risk factors for violence. It does not stop with schizophrenia, and of course alcohol and drug use are also major mental-health disorders that increase the risk of violence.
I believe that taken together, the physical- and mental-health risk factors that we have scrutinized in this chapter are convincing components of the anatomy of violence. We’ll see later that these constituent pieces are not unalterable. Indeed, we have continued the theme seen in the past two chapters, on broken brains and natural-born killers, that the environment has a role in shaping the biological infrastructure of the violent offender. We’ll now move further forward with this recipe for violence to understand how all the different ingredients that we have discussed so far blend together to form a lethal brew.