3.

The Biology of Behavioral Addiction

There’s a modern-day malady that affects two thirds of all adults. Its symptoms include: heart disease, lung disease, kidney disease, appetite suppression, poor weight control, weakened immune functioning, lowered resistance to disease, higher pain sensitivity, slowed reaction times, mood fluctuations, depressed brain functioning, depression, obesity, diabetes, and certain forms of cancer.

That malady is chronic sleep deprivation, which is rising in the wake of smartphones, e-readers, and other light-emitting devices. Sleep deprivation is behavioral addiction’s partner—the consequence of persistent overengagement. It’s a global problem that has recently attracted plenty of attention, including from entrepreneur and author Arianna Huffington. At the 2016 World Economic Forum in Davos, Huffington discussed her forthcoming book on sleep, titled The Sleep Revolution:

I got an email two hours ago from the official Davos establishment, which was a sleep survey of the world. It shows that people spend more time on their digital devices than sleeping . . . I think it’s really interesting to look at the relationship between technology and taking care of ourselves. Because we’re obviously all addicted to technology. So how can we put it in its place? And not on your nightstand. That is the key guys—do not charge your phones by your bed.

Huffington was wise to focus on smartphone charging. Ninety-five percent of adults use an electronic device that emits light in the hour before bed, and more than half check their emails overnight. Sixty percent of adults aged between eighteen and sixty-four keep their phones next to them when they sleep, which might explain why 50 percent of adults claim they don’t sleep well because they’re always connected to technology. Sleep quality has declined dramatically in the past half century, particularly over the past two decades, and one of the major culprits is the bluish light that emanates from many of these electronic devices.

For millennia, blue light existed only during the daytime. Candles and wood fires produced reddish-yellow light, and there was no artificial lighting at night. Firelight isn’t a problem, because the brain interprets red light as a signal for bedtime. Blue light is a different story, because it signals morning. So 95 percent of us are inducing jet lag at night by telling our bodies that the day is beginning just before we go to bed.

Normally, the pineal gland buried deep in your brain produces a hormone called melatonin at night. Melatonin makes you sleepy, which is why people who suffer jet lag take melatonin supplements before bed. When blue light hits the back of your eyes, the pineal gland stops producing melatonin, and your body prepares for the day. In 2013, a group of scientists measured how much melatonin thirteen volunteers produced after using an iPad for two hours late at night. When those volunteers wore orange goggles—to simulate evening light—they produced plenty of melatonin, which prepared their bodies for bed. When they wore blue goggles (and to some extent when they used the iPad without goggles), their bodies produced significantly less melatonin. The researchers urged “manufacturers to design [sleep-cycle]-friendly electronic devices” with backlights that turned progressively more orange at night. A second study, this time without goggles, found the same effect: people produce less melatonin, sleep more poorly, and feel more tired when they use an iPad before bed. In the long run, our technology compulsions are damaging our health.

As much as blue light hampers our ability to sleep, the real damage of behavioral addiction happens when we’re wide awake, obsessively juggling laptops and tablets, fitness trackers and smartphones.

The human brain exhibits different patterns of activity for different experiences. One clump of neurons fires when you imagine your mother’s face; a different clump when you imagine the house where you grew up. These patterns are fuzzy, but by looking at a person’s brain you can tell roughly whether she’s thinking about her mother or her first home.

There’s also a pattern that describes the brain of a drug addict as he injects heroin, and a second that describes the brain of a gaming addict as he fires up a new World of Warcraft quest. They turn out to be almost identical. Heroin acts more directly, generating a stronger response than gaming, but the patterns of neurons firing across the brain are almost identical. “Drugs and addictive behaviors activate the same reward center in the brain,” according to Claire Gillan, a neuroscientist who studies obsessive and repetitive behaviors. “As long as a behavior is rewarding—if it’s been paired with rewarding outcomes in the past—the brain will treat it the same way it treats a drug.” What makes drugs like heroin and cocaine more dangerous in the short-term is that they stimulate the reward center much more strongly than behaviors do. “Cocaine has more direct effects on the neurotransmitters in your brain than, for example, gambling, but they work by the same mechanism on the same systems. The difference is in their magnitude and intensity.”

This idea is quite new. For decades, neuroscientists believed that only drugs and alcohol could stimulate addiction, while people responded differently to behaviors. Behaviors might be pleasurable, they suggested, but that pleasure could never rise to the destructive urgency associated with drug and alcohol abuse. But more recent research has shown that addictive behaviors produce the same brain responses that follow drug abuse. In both cases, several regions deep inside the brain release a chemical called dopamine, which attaches itself to receptors throughout the brain that in turn produce an intense flush of pleasure. Most of the time the brain releases only a small dose of dopamine, but certain substances and addictive experiences send dopamine production into overdrive. Warming your hands by a log fire on a cold night or taking a sip of water when you’re thirsty feels good, but that sensation is dramatically more intense for an addict when he injects heroin or, to a lesser extent, begins a new World of Warcraft quest.

At first the upsides dramatically outweigh the downsides as the brain translates the rush of dopamine into pleasure. But soon the brain interprets this flooding as an error, producing less and less dopamine. The only way to match the original high is to up the dosage of the drug or the experience—to gamble with more money or snort more cocaine or spend more time playing a more involving video game. As the brain develops a tolerance, its dopamine-producing regions go into retreat, and the lows between each high dip lower. Instead of producing the healthy measure of dopamine that once inspired optimism and contentment in response to small pleasures, these regions lie dormant until they’re overstimulated again. Addictions are so pleasurable that the brain does two things: first it produces less dopamine to dam the flood of euphoria, and then, when the source of that euphoria vanishes, it struggles to cope with the fact it’s now producing far less dopamine than it used to. And so the cycle continues as the addict seeks out the source of his addiction, and the brain responds by producing less and less dopamine after each hit.

As a kid I was terrified of drugs. I had a recurring nightmare that someone would force me to take heroin and that I’d become addicted. I knew very little about addiction, but I pictured myself frothing at the mouth in a bleak treatment center. As time passed I realized that drug pushers weren’t going to waste their time on a neurotic seven-year-old, but one part of the nightmare stuck with me: the idea that a person could become addicted against his will; that if you happened to come into contact with an addictive substance, you’d develop an addiction. If addiction were simply a brain disorder, my seven-year-old self would have been right: flood the brain with dopamine and you create an addict. But that’s not how addiction works at all. Since your brain fundamentally reacts the same way to any pleasurable event, there has to be another ingredient—otherwise we’d all develop crippling ice cream addictions from an early age. (Just imagine the dopamine shock that follows a toddler’s first taste of ice cream.)

The missing ingredient is the situation that surrounds that rise in dopamine. The substance or behavior itself isn’t addictive until we learn to use it as a salve for our psychological troubles. If you’re anxious or depressed, for example, you might learn that heroin, food, or gambling lessen your pain. If you’re lonely, you might turn to an immersive video game that encourages you to build new social networks.

“We have systems for parenting and love, and those systems push us to persist despite negative consequences,” Maia Szalavitz, a writer who focuses on addiction, explains. “The system that’s designed for that sort of behavior is the template for addiction. When this system becomes misaligned, you get addictions.” Each of the systems that Szalavitz refers to is a collection of instinctive survival behaviors, like the drive to care for your children or to find a romantic partner. The same instincts that push us to persevere in the face of pain and difficulty can also propel fanaticism and damaging addictive behavior.

In one article, Szalavitz explains that no one else can turn you into an addict. “Pain patients cannot be ‘made addicted’ by their doctors,” Szalavitz says. “In order to develop an addiction, you have to repeatedly take the drug for emotional relief to the point where it feels as though you can’t live without it . . . it can only happen when you start taking doses early or take extra when you feel a need to deal with issues other than pain. Until your brain learns that the drug is critical to your emotional stability, addiction cannot be established.” Addiction isn’t just a physical response; it’s how you respond to that physical experience psychologically. To underscore the point, Szalavitz turns to heroin, the most addictive and dangerous illicit drug. “To put it bluntly, if I kidnap you, tie you down, and shoot you up with heroin for two months, I can create physical dependence and withdrawal symptoms—but only if you go out and use after I free you will you actually become an addict.”

“Addiction isn’t about ‘breaking’ your brain, or ‘hijacking’ your brain, or ‘damaging’ your brain,” Szalavitz says. “People can be addicted to behaviors, and even to the experience of love. Addiction is really about the relationship between the person and the experience.” It isn’t enough to ply someone with a drug or a behavior—that person also has to learn that the experience is a viable treatment for whatever ails them psychologically.

The highest risk period for addiction is early adulthood. Very few people develop addictions later in life if they haven’t been addicted in adolescence. One of the major reasons is that young adults are bombarded by a galaxy of responsibilities that they’re not equipped to handle. They learn to medicate by taking up substances or behaviors that dull the insistent sting of those persistent hardships. By their midtwenties, many people acquire the coping skills and social networks that they lack in adolescence. “If you aren’t using drugs as a teenager, you’re probably also learning to deal with your troubles using other methods,” Szalavitz said. So you develop a degree of resilience by the time you emerge through the gauntlet of adolescence.

The most striking thing Szalavitz told me was that addiction is a sort of misguided love. It’s love with the obsession but not the emotional support. That idea might sound fluffy, but it’s grounded in science.

In 2005, an anthropologist named Helen Fisher and her colleagues placed infatuated lovers in a brain scanner. She described their findings in an article titled “Love Is Like Cocaine”:

I felt like jumping in the sky. Before my eyes were scans showing blobs of activity in the ventral tegmental area, or VTA, a tiny factory near the base of the brain that makes dopamine and sends this natural stimulant to many brain regions . . . This factory is part of the brain’s reward system, the brain network that generates wanting, seeking, craving, energy, focus, and motivation. No wonder lovers can stay awake all night talking and caressing. No wonder they become so absent-minded, so giddy, so optimistic, so gregarious, so full of life. They are high on natural “speed.” . . . Moreover, when my colleagues re-did this brain scanning experiment in China, their Chinese participants showed just as much activity in the VTA and other dopamine pathways—the neurochemical pathways for wanting. Almost everyone on earth feels this passion.

In the 1970s, a psychologist named Stanton Peele published Love and Addiction, explaining that the very healthy attachment we feel toward people we love can also be destructive. This same attachment could be directed toward a bottle of vodka, a syringe of heroin, or an evening at the casino. They’re impostors because they soothe psychological discomfort in the same way that social support makes hardship easier—but they soon replace short-term pleasure with protracted pain. The capacity for love is the result of millennia of evolution. This makes people well-designed to raise offspring and to shepherd their genes into the next generation—but also susceptible to addiction.

Destructiveness is a critical part of addiction. There are many ways to define addiction, but the broadest definitions go too far because they include acts that are healthy or essential for survival. In a 1990 editorial in the British Journal of Addiction, a psychiatrist named Isaac Marks claimed that, “Life is a series of addictions and without them we die.” Marks titled the editorial “Behavioral (Non-Chemical) Addictions,” and he was being provocative for good reason. Behavioral addictions were relatively new to the field of psychiatry:

Every few moments we inhale air. If deprived of it, within seconds we strive to breathe, with immense relief when we succeed. More prolonged deprivation causes escalating tension, severe withdrawal symptoms of asphyxiation and death within minutes. On a longer time scale, eating, drinking, defaecation, micturition and sex also involve rising desires to perform an act; the act switches off the desire, which returns within hours or days.

Marks was right: breathing seemed to mirror the properties of other addictions. But the idea of addiction isn’t interesting or useful if it describes every single activity that plays a role in our survival. It doesn’t make sense to call a cancer patient an addict because she needs her chemotherapy medication. Addictions should, at the very least, leave our chances of surviving unchanged; as soon as they mirror the life-sustaining properties of breathing, eating, and chemotherapy drugs, they’re no longer “addictions.”

Stanton Peele linked love and addiction in the 1970s, arguing that love drove addiction when it was misdirected and turned toward dangerous targets. Like Marks fifteen years later, Peele was also arguing that addiction went beyond illegal drugs. That had been the position of scientists for decades, so much so that few of them were willing to accept that nicotine was addictive. Since smoking was legal, by their logic, its component parts couldn’t possibly be addictive. The term “addiction” had become so stigmatized that it was reserved for a small, closed set of substances. But the term wasn’t sacred to Peele. He pointed out that many smokers leaned on nicotine in the same way that heroin addicts relied on heroin as a psychological crutch, although heroin was more obviously damaging in the short-term. Peele’s perspective was heretical in the 1970s, but the medical world caught up in the 1980s and 1990s. Peele also recognized that any destructive crutch could become a source of addiction. A bored white-collar worker who turned to gambling for the thrill he lacked in the real world could develop a gambling addiction.

I approached Peele in researching this book, but he bristled when I mentioned behavioral addiction. “Sure,” he told me, signaling that he’d be happy to talk, “except I’ve never in my life used the term ‘behavioral addiction.’” To Peele the term was heretical, because it implied there was a meaningful difference between behavioral and substance addictions, a distinction he argues doesn’t exist because addiction isn’t about substances or behaviors or brain responses. Addiction, to Peele, is “an extreme, dysfunctional attachment to an experience that is acutely harmful to a person, but that is an essential part of the person’s ecology and that the person cannot relinquish.” That’s how he defined it decades ago, and that’s how he sees it today. The “experience” is everything about the context: the anticipation of the event, and the behavior of carefully lining up the needle, the charred spoon, and the lighter. Even heroin—an addictive substance if ever there was one—makes its way to the body via a chain of behaviors that themselves become part of the addiction. If even heroin addiction is to some extent “behavioral,” you can see why Peele avoided the term altogether.

Peele may not have used the term “behavioral addiction,” but for decades he has separated addictive behaviors and addictive substances in his books. For example, the sixth chapter of Peele’s book, The Truth About Addiction and Recovery, written with psychiatrist Archie Brodsky in 1991, is titled “Addictions to Gambling, Shopping, and Exercise.” Peele and Brodsky asked, “Can one be addicted to gambling, shopping, exercise, sex, or love in the same sense that one is addicted to alcohol or drugs?” Their answer was yes—that “any activity, involvement, or sensation that a person finds sufficiently consuming can become an addiction . . . addiction can be understood only in terms of the overall experience it produces for a person . . . and how these fit in with the person’s life situation and needs.” Peele and Brodsky were also quick to dismiss the idea that any pleasurable, endorphin-producing activity was an addiction. “Endorphins don’t make people run until their feet bleed or eat until they puke,” they argued. Just because runners experience a “high” doesn’t make them addicts. They refused to call gambling, shopping, and exercise compulsions “diseases,” but they allowed that those activities were capable of inspiring addictive behaviors.

Peele was marginalized for decades. He railed against abstinence and Alcoholics Anonymous, and wrote again and again that addiction wasn’t a disease. Rather, it was the association between an unfulfilled psychological need and a set of actions that assuaged that need in the short-term, but was ultimately harmful in the long-term. Peele was often inflammatory and always provocative, but his central message was unchanged: that any experience could be addictive if it seemed to soothe psychological distress. Peele’s ideas have slowly drifted to the mainstream. Though the American Psychiatric Association (APA) still considers addiction a disease, four decades after Peele first linked love and addiction, the APA has acknowledged that addiction isn’t limited to substance abuse.

Every fifteen years or so the APA releases a new edition of its bible, the Diagnostic and Statistical Manual of Mental Disorders (DSM). The DSM catalogs the signs and symptoms of dozens of psychiatric disorders, from depression and anxiety to schizophrenia and panic attacks. When the APA released the fifth edition of the DSM in 2013, it added behavioral addiction to its list of official diagnoses, and abandoned the phrase substance abuse and dependence in favor of addictions and related disorders. Psychiatrists had been treating behavioral addicts for years, and now the APA was catching up.

The APA also made clear that merely depending on a substance or behavior wasn’t enough to warrant a diagnosis of addiction. Many hospital patients depend on opiates, for example, but that doesn’t make all hospital patients opium addicts. The missing ingredients are the sense of craving that comes from an addiction, and the fact that addicts know they’re ultimately undermining their long-term well-being. A hospital patient who relies on morphine while he recovers from surgery is doing what’s best both in the short-term and the long-term; a morphine addict knows that his addiction combines short-term bliss and long-term damage. A number of current and former behavioral addicts told me the same thing: that consummating their addictions is always bittersweet. It’s impossible to forget that they’re compromising their well-being even as they enjoy that first rush of gratification.

The APA is only now endorsing the link between substance addiction and behavioral addiction, but isolated researchers have been making similar claims for decades. In the 1960s, even before Peele began publishing his ideas, a Swedish psychiatrist named Gösta Rylander noticed that dozens of tormented drug addicts were behaving like distressed wild animals. When confined to small spaces, animals soothe themselves by repeating the same actions over and over again. Dolphins and whales swim in circles, birds pluck their own feathers, and bears and lions pace within their enclosures for hours. By some reports, 40 percent of caged elephants march in circles and rock back and forth in a desperate quest for comfort.

These are universal signs of distress, so Rylander was worried to see similar behavior in regular amphetamine users. One patient collected and arranged hundreds of rocks by size and shape, and then jumbled them so he could begin the process from scratch. Dozens of motorcyclists in a gang of amphetamine users rode around the same suburban block two hundred times. A man picked at his hair incessantly, and a woman filed her nails for three days until they bled. When Rylander asked them to explain what they were doing, they struggled to concoct sensible answers. They knew they were behaving strangely, but they felt compelled to continue. Some of them were driven by an intense pathological curiosity, while others found the act of repetition soothing. Rylander reported what he saw in a journal article, where he labeled the behavior punding, a Swedish word that means blockheadedness or idiocy. Most interesting to Rylander, though, was that for these patients there was no line between drug addiction and behavioral addiction. One bled into the other, and they were similarly harmful, soothing, and irresistible.

Rylander died in 1979, but left a significant legacy. A growing circle of doctors and researchers reported punding in cocaine addicts and other drug users, and Rylander’s paper was cited hundreds of times. Punding behaviors are often bizarre, but they affected exactly who experts might have predicted: heavy drug users. That was true, at least, until the early 2000s, when a small group of neuroscientists began to see punding and other odd repetitive behaviors in the least likely of suspects.

In the early 2000s, Andrew Lawrence, a neuroscience professor at Cardiff University, and some of his colleagues noticed a range of strange addictive behaviors in people suffering from Parkinson’s disease. There’s almost no overlap between the stereotypical personalities of heavy drug users and Parkinson’s patients. Where drug users are young and impulsive, Parkinson’s patients tend to be elderly and sedate. More than anything, they hope to enjoy the final decades of their lives without suffering through the muscle tremors that are typical of the disease. The only overlap, in fact, is that these Parkinson’s patients were using a very strong drug to treat their tremors. “Parkinson’s results from a dopamine deficit, so we treat the disease with drugs that replace dopamine,” Lawrence said. Dopamine is produced by a number of brain regions, and it produces a wide variety of effects. It controls motion (hence the tremors in Parkinson’s patients) and plays a major role in shaping how people respond to rewards and pleasure. Dopamine targets Parkinsonian tremors, but also happens to introduce a form of pleasure or reward. Many patients, left to their own devices, develop addictions to dopamine replacement drugs, so neurologists monitor their dosages very closely. But that wasn’t what fascinated and troubled Lawrence most.

“Patients were hoarding their medication, and we happened to notice that some of them were also displaying behavioral addictions,” Lawrence said. “So they would report problem gambling, problem shopping, binge-eating, and hypersexuality.” In 2004, Lawrence catalogued some of these symptoms in a staggering review paper. One man, an accountant who had been a dedicated and careful saver for half a century, developed a gambling habit. He had never gambled before, but suddenly he felt drawn to the thrill of risk. At first he gambled conservatively, but soon he was gambling a couple of times a week, and then every day. His hard-won retirement savings shrank slowly at first, and then more quickly, until he went into debt. The man’s wife panicked and asked their son for money, but their son’s contribution merely fueled the man’s addiction. One day his wife found the man rummaging through the garbage, hoping to retrieve the lottery tickets she’d torn up earlier that day. Worst of all, the man couldn’t explain the change in his character. He didn’t want to gamble, or to squander his life savings, but he couldn’t help himself. When he fought the tendency to gamble it occupied his every thought. Only gambling seemed to relax him.

Other elderly patients developed sexual fetishes, and pestered their husbands and wives for sex throughout the day. One man, a lifelong fashion conformist, took to dressing up like a prostitute. Others developed addictions to Internet pornography. Lifelong health nuts binged on candy and chocolates and put on mountains of weight in a few short months. Strangest of all, perhaps, was the man who couldn’t stop giving away his money. When his bank account was empty, he began giving away his possessions instead. When Billy Connolly, the celebrated Scottish comedian, developed Parkinson’s in his late sixties, he began taking dopamine replacement drugs. He, too, succumbed to behavioral addictions and had to stop treatment. “The doctors took me off the medication, because the side effects were stronger than the effects,” Connolly told Conan O’Brien on a late-night talk show appearance. “I asked what the side effects were, and they said, ‘an overriding interest in sex and gambling.’” Connolly makes light of the anecdote on TV, but without treatment his tremors are becoming increasingly severe. The drugs are so strong that up to half of all patients seem to develop some of these side effects.

Lawrence argued that these patients were simply enacting whatever behaviors came to them most naturally. These behaviors, called stereotypies, depend on “individual life histories,” Lawrence wrote. “For example, office workers stereotypically shuffle papers, a seamstress will collect and arrange buttons.” A sixty-five-year-old businessman repeatedly dismantled and reconstructed pens, and tidied an already immaculate space on his desk. A fifty-eight-year-old architect tore down and reconfigured his home office over and over again. A fifty-year-old carpenter collected hardware tools and unnecessarily felled a tree in his yard. These familiar actions became a source of comfort because they came so fluently and demanded very little thought.

Lawrence and Rylander before him were witnessing the blurred line between substance addictions and behavioral addictions. Like drugs or alcohol, stereotypies offered just one more route to soothe a tormented psyche. Lawrence pointed out this overlap by noting that many of the patients who were stuck in a behavior loop also overdosed on their dopamine-producing medication. Those with aggressive Parkinson’s were often fitted with a small pump that administered the drugs internally. Though they were told to obey a schedule, they could push a button to administer a fresh dose of the drug when their symptoms flared. Many of them began by following the schedule, but they soon learned that the drug also made them feel good. Some of the patients who became addicted to the drug also developed behavioral addictions, and they would jump back and forth between the two. One day they might take a few extra doses of the drug, and the next they might shuffle papers for several hours in the morning before collecting and arranging rocks from the garden in the afternoon. Sometimes they’d do both at the same time, self-medicating with both drugs and soothing behaviors. There was no material difference between these two routes to addiction; they were essentially two versions of the same malfunctioning program.

In the 1990s, a neuroscientist at the University of Michigan named Kent Berridge was trying to understand why addicts continued using drugs as their lives deteriorated. One obvious answer was that addicts get so much pleasure from their addictions that they’re willing to sacrifice long-term well-being for a jolt of immediate bliss—that they fall in dysfunctional love with a partner that destroys them in return. “Twenty years ago we were looking for mechanisms of pleasure,” Berridge said. “And dopamine was the best mechanism of pleasure out there, and everybody knew it was involved in addiction. So we set out to gather more evidence to show that dopamine was a mechanism of pleasure.” To Berridge and many other researchers the link seemed obvious—so obvious that he expected to find it quickly so he could move on to answer newer, more interesting questions.

But the result turned out to be elusive. In one experiment, Berridge gave rats a delicious sugary liquid and watched as they licked their lips with pleasure. “Like human infants, rats lick their lips rhythmically when they taste sweetness,” Berridge said. Rat researchers learn to interpret different rattish expressions, and this one was the gold standard for pleasure. Based on his understanding of dopamine, Berridge assumed that each rat’s tiny brain was flooding its host with dopamine each time it tasted the sweet liquid, and this rise in dopamine drove the rat to lick its lips. Logically, if Berridge stopped the rat from producing dopamine, it should stop licking its lips. So Berridge performed a kind of brain surgery on the rats to stop them from producing dopamine, and fed them the liquid again.

The rats did two things after surgery, one of which surprised Berridge and one of which didn’t. As he expected, they stopped drinking the sugary liquid. The surgery had knocked out their appetite by preventing their brains from producing dopamine. But the rats continued to lick their lips when he fed them the sugar water directly. They didn’t seem to want it—but when they tasted it, they seemed to get just as much pleasure as they had before the surgery. Without dopamine they lost their appetite for sugar water, but still enjoyed it when they tasted it anyway.

“It took about ten years for this to sink in among the neuroscience community,” Berridge says. The findings contradicted what neuroscientists long felt they knew to be true. “For a number of years people in the neuroscience world told us, ‘No, we know dopamine drives pleasure; you have to be wrong.’ But then evidence started to come in from studies on humans, and now very few researchers doubt our findings. In those studies, researchers would give people cocaine or heroin, as well as a second drug that was designed to block dopamine production. Blocking dopamine didn’t reduce the pleasure they felt—but it did reduce the amount they took.”

Berridge and his colleagues had shown that there was a big difference between liking a drug and wanting a drug. Addiction was about more than just liking. Addicts weren’t people who happened to like the drugs they were taking—they were people who wanted those drugs very badly even as they grew to dislike them for destroying their lives. What makes addiction so difficult to treat is that wanting is much harder to defeat than liking. “When people make decisions, they privilege wanting over liking,” Berridge said. “Wanting is much more robust and big and broad and powerful. Liking is anatomically tiny and fragile—it’s easily disrupted and it occupies only a very small part of the brain. In contrast, it’s not easy to disrupt the activation of an intense want. Once people want a drug, it’s nearly permanent—it lasts at least a year in most people, and may last almost a whole lifetime.” Berridge’s ideas explain why relapse is so common. Even after you come to hate a drug for ruining your life, your brain continues to want the drug. It remembers that the drug soothed a psychological need in the past, and so the craving remains. The same is true of behaviors: even as you come to loathe Facebook or Instagram for consuming too much of your time, you continue to want updates as much as you did when they still made you happy. One recent study suggests that playing hard to get has the same effect: an unattainable romantic partner is less likable but more desirable, which explains why some people find emotionally unavailable partners alluring.

Liking and wanting overlap most of the time, which clouds their differences. We tend to want things that we like, and vice versa, because most pleasant things are good for us, and most unpleasant things are bad for us. The baby rats in Berridge’s studies had evolved to instinctively like the taste of sugar water, because sweet substances tend to be both harmless and rich in calories. Their ancestor rats who gravitated toward sweet foods tended to live longer and to mate with other rats, so their sweet-tooth proclivity was passed down from one generation to the next. The rats who ate bitter foods were more likely to die, either from poisoning or from malnutrition. Very few truly bitter foods are packed with nutrients, and from a young age we avoid the many bitter plants and roots that happen to be toxic. Though they’re often linked, Berridge showed that liking and wanting take different paths in the case of addiction. The depths of addiction are no fun at all, which is another way of saying that addicts crave a hit without liking the experience. Stanton Peele likened addiction to misguided love, and falling in love with the wrong person is a classic case of wanting without liking. Loving the wrong person is so common that we have stereotypes for the “guy who’s no good” and the “femme fatale.” We know they’re no good for us, but we can’t help wanting them.

Although Berridge spends more time investigating drug addiction, like Stanton Peele and Andrew Lawrence he believes his ideas also apply to behavioral addictions. “We always knew drugs could influence these brain systems, but we didn’t know the same about behaviors. Over the past fifteen years or so, we’ve come to learn that the same is true of behaviors—and the process works through the same brain mechanisms.” Just as drugs trigger dopamine production, so do behavioral cues. When a gaming addict fires up his laptop, his dopamine levels spike; when an exercise addict laces her running shoes, her dopamine levels spike. From there, these behavioral addicts look a lot like drug addicts. Addictions aren’t driven by substances or behaviors, but by the idea, learned across time, that they protect addicts from psychological distress.

The truth about addiction challenges many of our intuitions. It isn’t the body falling in unrequited love with a dangerous drug, but rather the mind learning to associate any substance or behavior with relief from psychological pain. In fact, addiction isn’t about falling in love; as Kent Berridge showed, all addicts want the object of their addiction, but many of them don’t like it at all. As for Isaac Vaisberg, Andrew Lawrence’s Parkinson’s patients, and Rat No. 34, addiction persists even after its appeal wanes, leaving intact the desire for gaming, tidying up obsessively, or self-administering a shock long after the pleasure has gone.