8

THE DARK SIDE OF DESIRE

SEEKING HAPPINESS, WE sometimes risk becoming the plaything of our positive feelings. Because the pleasure of the new summer dress is short-lived pleasure, we go out and buy a matching pair of Prada shoes. They were, after all, on sale. How could we resist, even if they were the wrong size? Many people who have reasonable incomes live on the edge of their credit. Pleasure is fleeting. Who hasn’t tried to overcome the sense of excess that follows a cheeseburger with a double scoop of caramel swirl extra-rich ice cream—thereby undoing all the hard dieting of the previous days?

Desire can take on a life of its own, as the Canadian neuroscientist James Olds demonstrated with a legendary experiment in 1954. He placed a thin electrode into the hypothalamus of rats, the region of the brain that is responsible for desire. He attached the wire to a switch that the rats could activate to give themselves a small electric charge that would stimulate this part of the brain. The result was stunning: after a very short time, it was as if the rats were wedded to the switch. The poor creatures forgot everything else and kept pushing it again and again as if possessed, clocking up to six thousand self-stimulations an hour. To Olds’s astonishment, they lost all interest in sex, and even in food and drink. For a bit of happiness they risked death! After a few days, the scientist turned off the stimulator and spared their lives.1

What was it that drove these rats onto such a self-destructive path? By pressing the handle, they were able to turn on their expectation system and flood their brains with dopamine. As we’ve seen, this transmitter signals the sighting of a reward and sets all kinds of bodily functions in motion to ensure that the organism actually attains its goal. Above all, dopamine ensures that the brain records the beneficial situation as positive. It becomes programmed for repetition. It was the nectar-suffused blossom that caused the bee to release dopamine, thus establishing it as the goal to which the bees would fly in the future. With Olds’s rats, it was the lever that took on this role, rendering them incapable of attending to anything else—each time further strengthening the programming and thus the compulsion.2

In this experiment we can see the downside of positive feelings. If a stimulus triggers desire repeatedly, the functioning of large parts of the brain is changed. Becoming superpowerful, desire transforms people into driven creatures who know no limits and have lost their sense of reality. In New Zealand, the researcher John Reynolds proved recently that the brain’s wiring changes under the influence of dopamine. Using an experimental procedure similar to Olds’s, he found that as soon as ten minutes after first pressing the lever, the coupling strength of the neurons in the rats’ midbrain, which controls external actions, had changed. The programming for pleasure had begun.3

AIMLESS DRIVE

Like many things that have multiple applications, the brain circuits for pleasure are vulnerable to misuse. It is only their variety and adaptability that enable them to seize our personalities. Though it might seem surprising, we don’t have one circuit that controls our desire to eat, another for love, and a third for social recognition. Instead we are equipped with a single, all-purpose system for desire and its gratification. Therein lie both its power and its danger.

This insight, too, we humans owe to rats. Once again, scientists placed electrodes in the hypothalamus—this time to expose the direct effects of pleasure on behavior. As soon as the researchers stimulated the brain circuits for desire, the animals became lively and active. But how were they to channel their need for action? Having been stimulated artificially, they had no goal. So they looked for one. They began to do everything that a rat can do—eat, drink, sniffle, gnaw, clean itself, copulate, carry things around the cage, kill mice, carry their young back to their nest.

It didn’t seem to matter what the rats did, as long as they did something. If the scientists took the food away from an electrically stimulated rat that was about to eat, it ran to the water bottle and drank. If that was removed, the rat sought out a partner with which it could mate. This aimlessness went so far that after their water had been poured from a bottle into a bowl the thirsty rats would eat food rather than drink.4 The more dopamine circulated in their brains, the more interchangeable the activities seeking the release of their arousal became. Thus, the researchers observed agitation in its purest form: activity counted for everything, the goal for nothing.

The functioning of desire’s mechanisms explains this phenomenon. Dopamine, the most important transmitter in this system, doesn’t relay information as such. Rather, it alters the readiness of the neurons to receive messages—and thus it changes the way in which the organism reacts to its environment. This strengthens whatever emotions happen to dominate at a particular moment. A hungry rat will look for food with even greater enthusiasm. If we stimulate the dopamine system of an animal that is full, it will lunge for whatever is offered.

People are no different. Nothing beats boredom like desire. It lifts our mood; attaining something lifts it still more. Exactly what changes the mood isn’t so important. A dream dress, a platinum credit card, running for a seat on the school board—anything can keep the pleasure machine running. What matters is the inner condition of desire, the anticipation of conquest. For this we are willing to give almost everything.

THE LAS VEGAS PRINCIPLE

If so predisposed, a gourmand can become a compulsive eater; a sports fan, an obsessive jogger; a happy winner, a pathological gambler. All these compulsive behaviors arise in similar ways.

In the case of compulsive gamblers, it’s the hope of financial reward that sets the pathological anticipation in motion. The surge of dopamine is released when the coins tumble out of the slot machine, or when a gambler at the next table cleans up—a “fiery tingling over the whole body” is how the Russian novelist Fyodor Dostoyevsky, who lost all he had at the roulette table, described the physiological sensation. The ringing of a few coins is enough to transfix hordes of otherwise reasonable people in front of a metal box for hours, where, like robots, they pull on a handle two or three times a minute, hoping that they, too, may set off the magical ringing. It isn’t by chance that this reminds us of those rats in the lab that pushed the lever to stimulate themselves, and the same thing is happening in the brains of both.

With every successful wager, more dopamine is released. Each time, the linking of “handle” with “positive feeling” is strengthened in the brain, and with it the compulsion to pull the one-armed bandit—exactly as with the rats. That the slot machines ultimately spit out less money than the gamblers put into them is something the brain’s expectation system can’t know.

The Harvard psychiatrist Hans Breiter has shown that gambling activates the same synapses in the brains of gamblers and addicts, and even in volunteer subjects who aren’t dependent. But unlike the compulsive gambler, someone who plays occasionally still has her expectation system under control.5

WHEN PLEASURE RUNS AMOK

That the same mechanisms responsible for everyday learning and anticipation (and therefore necessary for living) also govern addiction is probably the least intuitive insight that the study of positive feelings provides. But for just this reason research into addiction also gives us a profound understanding of the minds of healthy people. Addiction is an accident that happens in the course of the human search for happiness.

Evolution hadn’t planned for this kind of self-inflicted harm, because it couldn’t plan for the distant future. A hundred million years ago, when many of our behavioral patterns were being formed in our genes, it couldn’t be foreseen that large primates would one day brew alcoholic drinks, build gambling halls, and synthesize cocaine. And ten generations ago, when large-scale hunger was commonplace, no one could have envisioned the mechanization of agriculture that would contribute to obesity as a widespread pathology.

We need to understand dependency as desire that has gone out of control in the absence of counterforces. Even the Seven Deadly Sins can be seen as an overshooting of our natural striving for happiness. Pride is exaggerated self-love, covetousness is frugality gone haywire. We become envious when our natural tendency to orient ourselves toward others gets the upper hand. People yield to gluttony when the organism doesn’t respond to nourishment with a sense of satiety, and to lust when sex is so unsatisfying that we want ever more of it. Anger is unbridled aggressiveness, sloth a pleasant relaxation that knows no end.

Drugs work exactly like the fatal levers in the gambling hall and in the rat’s cage, for they too give the brain a dopamine lift. Under the influence of alcohol, the dopamine level doubles, and with nicotine and cocaine it increases threefold, as the Italian toxicologist Gaetano Di Chiara has determined. Because dopamine enhances our alertness, a cigarette gives us a sense of pleasant arousal and makes us feel more energetic and capable than before. Similarly, we often become optimistic after drinking a glass or two of wine.6

The same mechanism is at the bottom of all addictions, and drugs differ only in the way they set it off. Nicotine releases dopamine directly in that it activates the responsible neurons. Alcohol, heroin, and morphine increase the dopamine level indirectly, inhibiting neurons that normally oppose the anticipation system. Finally, cocaine ensures that once dopamine has been released, it remains in circulation longer. (Normally it disappears quickly into the cell walls of the brain.) Like Oliver Sacks’s patient Leonard under the effect of L-Dopa, people who sniff the white powder feel the rush of omnipotence.

The critical factor is how dopamine is released. At the crucial moment of release, the brain links the sight of the drug and the desire for it ineradicably. An addicted brain that recognizes a cigarette immediately orders “Light it!” or, stimulated by “bottle,” gives the order to drink. Merely the image of an injection can suffice to set off a heroin addict’s synapses.7 In this way, nicotine, alcohol, and cocaine slip into the brain structures responsible for positive feelings, like the soldiers in the Trojan horse: drugs seize the brain.

HOW WE ALLOW OURSELVES TO BE SEDUCED

Can you remember your first cigarette? Most people find it an awful experience. The smoke scratched your throat. You could barely hide your need to cough from the kids who were watching. Some of us experienced our first beer similarly. If we’re honest, most of us will admit that we persisted in order to look cool, rather than because we really enjoyed the bitter taste.

Most adults can enjoy beer and cigarettes. We can even learn to enjoy the burning of chilies. But it wasn’t a pleasure at first. And it is hardly ever pleasure that drives people to alcohol and cigarettes. Even a laboratory rat wouldn’t suck on a liquor bottle of its own accord, although alcohol has the same effect on rats as it does on people. Scientists have to work hard to get rats to become addicted to alcohol. And the same is true for people: addictions are learned.8 The original motivation is almost always to assuage some kind of difficulty. The German writer Wilhelm Busch wrote that people who have cares also have liquor. And, it has to be said, vice versa.

Alcohol calms and dissipates fear. Cocaine has the short-term effect of a turbocharger on imagination and wit, thus seeming to help all those people who feel stupid and boring with their friends. Nicotine helps people endure boredom and stress; it stimulates and calms at the same time, but even more important, cigarettes give young people some kind of status among their friends, and they help break the social ice.

Many studies show that it’s not the search for pleasure that leaves people susceptible to drugs, but the wish to find an escape from life’s problems. Drug consumption increases almost automatically when the going gets tough. Alcoholism is widespread among the unemployed, as was heroin addiction among the American soldiers in Vietnam.9 Of these young men, 40 percent took heroin at least once to help them endure the horrors of war. Half of them took it so often that when they went off the drug, they experienced the symptoms of withdrawal.10

Even a brief unpleasantness can lead to increased drug use. American researchers asked experimental subjects who were not addicted to solve a difficult puzzle, all the while criticizing and demeaning them. Afterward, the volunteers were asked to participate in an experiment that was billed as a “drinking test”—they were told to evaluate and compare different alcoholic drinks. Those who had suffered the worst abuse drank significantly more than those who’d been treated appropriately. A third group that was given the opportunity to get back at their critics consumed normal quantities of alcohol—apparently vengeance diminished the need to drink away the anger.11

WHO BECOMES AN ADDICT?

Drugs help us forget. Clearly, however, not everyone who has worries takes drugs. And not everyone who takes drugs becomes an addict. There are many wine drinkers and even occasional cocaine users who never develop dependencies. The most likely to succumb to their addiction are cigarette smokers. Of all addictions, cigarettes are the most seductive—not only because they’re ubiquitous, but because nicotine has a direct effect on the dopamine system.12

Why can most people consume potentially addictive drugs without becoming dependent on them? The answer lies in the quality of their lives, and on their genes. Stress, for example, whatever its source, increases the probability that in the quest for a bit of relaxation you’ll succumb to alcohol, tobacco, or heroin addiction.

Some genetic factors that affect the risk of addiction are very straightforward. A high tolerance for the drug in question, for example, puts one at a much higher risk. By contrast, if drinking one glass too many results in a ghastly hangover, alcoholism is probably not in the cards.

Another genetic factor is the extent of one’s curiosity. There is a close connection between the enjoyment of novelty and the danger of becoming substance dependent. Dopamine plays a role in both, and whoever responds strongly to novelty, adventure, and dangerous situations also lives with a certain risk of becoming dependent. Scientists specializing in addiction have long known that rats that are especially vulnerable to dependency show more curiosity than other rats.13

The familiar D2 receptor for dopamine seems to play an important role here. Scientists at the Brookhaven National Laboratory near New York even managed to get alcohol-dependent rats off the bottle by using gene therapy to increase the number of dopamine receptors in their brains.14

Is it possible that in the distant future genetic intervention will result in fewer addictions? Right now it’s out of the question. The complex mechanisms that determine how genes influence drug consumption are still far from understood. Geneticists today are more interested in predicting a person’s tendency to addiction, so that he can act preventatively. People who have too few D2 receptors are especially at risk, says the Brookhaven National Laboratory addiction researcher Nora Volkow. A great-granddaughter of the Russian revolutionary Leon Trotsky, she established her reputation by examining the brains of human addicts. She discovered that addictions further diminish the number of D2 receptors (already low), and for years.

Thus people who are or were drug dependent live with a high probability of succumbing to a second addiction. Experiments show how morphine-dependent rats that have been broken of the habit then become dependent on alcohol. Almost every heroin addict is also dependent on cigarettes or alcohol. Addictions seize all of the person. People who began smoking or drinking in puberty are at still higher risk, for the young brain is especially malleable. There is no better protection against addiction than keeping children from using drugs.

CAUGHT IN A VICIOUS CYCLE

Someone who is once addicted is often aware only of the blind need for his drug. What keeps an addiction going is the brain’s programming, not enjoyment.

This is not to say that people can’t enjoy their dependency. Of course, cigarettes, beer, and strong drugs can bring forth pleasurable feelings. This is especially obvious with substances like heroin, which bear a chemical resemblance to opioids and thus stimulate a sense of euphoria. Nicotine and alcohol also cause a similar reaction, though less directly, and there’s no harm in occasional indulgence.

But people who use a drug regularly will need it in increasing doses. Its effect wears off as the brain gets dulled to it. Over time, the pleasure wanes, and then drug use is no longer about getting high but about maintaining a normal mood. A day without the drug becomes drab. Using it restores some sense of pleasure for a few hours, but it desensitizes the brain further, and the addict digs himself ever deeper into his dependency. At some point, the chain smoker and the alcoholic don’t get much satisfaction from their cigarettes and vodka. They maintain their habit because they’re hooked—the sense of pleasure is long gone.

Hardly anyone has described this condition as well as the songwriter Konstantin Wecker, who was addicted to cocaine: “What a feeling of horror there was when only a few more grams were left in the house. We tore down walls if we thought some might be stored there. We ripped furniture apart in the hope of finding any remains. It was pathetic, and I was disgusted with myself. My dealer was fair, and I loved him, and when I testified to that effect in court, it came from the heart.”15

Compared to what comes later, the physical symptoms of withdrawal are easy. The shivering and the shaking, the nausea and the hallucinations can be tempered with medication, and after a few weeks they disappear. What is much harder to contain is the need for the drugs that has been seared into the brain.

Many people think that an addict takes his drug primarily to preempt the symptoms of withdrawal. But this doesn’t explain why someone who was once addicted can still relapse after decades. Although the brain loses its insensitivity to the drug shortly after the often painful withdrawal, the number of ex-addicts who compulsively reach for a cigarette is legion, even after they’ve been clean for a long time.

To understand this phenomenon we need to realize that the brain creates volition and pleasure in different ways. Addiction distorts both. If a drug-free life seems bland, it’s because the drug has impaired the ability to enjoy. Addiction, on the other hand, comes about because the drug has insinuated itself into the brain’s systems for desire and reprogrammed them. And while the dulling of pleasure is reversible, the expectation system is permanently damaged.

The obduracy of addiction results from the powerful mechanisms of desire—the phenomenon of craving. Someone who was once addicted is often “trained” for life. To counteract it is like unlearning our mother tongue. The experience of addiction permanently transforms the functioning of the nerve cells in the brain, altering the way in which the genetic information is read and changed into proteins. The cells are now disposed to create substances that make the brain especially receptive to any stimuli connected with the drug. Connections that lie like thick cables between neurons in the brain cause these stimuli to release an immediate demand for the drug. They hardly ever revert to their prior condition. Neurobiologists can even see in individual brain cells exactly which rats they had succeeded in habituating to alcohol long before.

This doesn’t mean that people are helpless in the face of their addictions. Dependencies can be overcome. But people who were once addicted have to work their whole lives to overcome their illness—much as survivors of a heart attack have to change their habits if they don’t want to risk another one.

An addict can either attempt to avoid the siren song of the drug, or he can control the urge to give in to temptation. Both are difficult, for the brain doesn’t only link the substance itself with the craving, but also all the stimuli that were ever associated with it: clouds of smoke in a bar, seeing old friends, the aroma of a few drops of rum in a cake.

Elton John, one of countless pop stars with a successful withdrawal behind him, memorably describes the absurd torments that can be visited on an ex-addict: “Sometimes, when I fly over the snow-covered Swiss alps, I think that all the coke that I ever sniffed is lying down there.”16