Good Reasons for Bad Feelings

by Randolph M. Nesse

  The conflict is old. Philosophers in ancient Greece described the possible solutions.58 Hedonism recommended pursuing pleasure without restraint. Stoicism recommended pursuing virtue, putting up with pain, and practicing restraint to avoid being distracted by desire. Epicureanism recognized that suffering comes from pursuing desires, so it encouraged enjoying pleasures as they are available but keeping desires and social striving at a distance. Living with abundance creates new problems—but they are first-world problems many people would love to have.

  CHAPTER 13

  GOOD FEELINGS FOR BAD REASONS

  Then Noah began farming and planted a vineyard. He drank of the wine and became drunk, and uncovered himself inside his tent.

  —Genesis 9:20–21 (New American Standard Bible)

  Our team of consulting psychiatrists was making rounds on the medicine ward. The internists asked us to see a forty-five-year-old woman whose liver was failing. They told her she would die if she continued drinking. She told them she didn’t care. They thought that was suicidal and decided it was time to invite the shrinks for a visit.

  She looked as if she were already dead. Her skin was puffy and yellow, her arms had no muscle, and her abdomen was so swollen she looked pregnant. The senior psychiatrist in our group asked her, very gently, about her use of alcohol. She replied, “I like it. You can’t stop me. Nothing can.” The psychiatrist pointed out that continuing to drink would cause her death in a matter of weeks and that treatment was available. “So?” she said. “I guess I like liquor better than life.”

  When he tried to engage her further, she interrupted him, paused, and glared at the half circle of young doctors around the foot of her bed. “I’ve been to rehab ten times, and I’ve always gone back to the sauce. It won’t be any different now. I don’t want to quit. You can’t help. No one can. I have made my decision. Leave me alone.” Portraying her helplessness as a choice gave her a shred of self-respect, but only that of a prisoner on the gallows tightening the noose around her own neck. The next day she was gone, signed out of the hospital, on her way to becoming one of the 100,000 Americans alcohol kills each year.1

  Substance abuse takes a staggering toll. In the United States, 30 percent of adults have at some point qualified for a diagnosis of alcohol abuse or alcoholism.2 In 2015 8.4 percent of men and 4.2 percent of women in the United States had an alcohol use disorder and 10 percent of the population used illicit drugs.3 Tobacco use is more common and more deadly. Worldwide, more than a billion humans are addicted to nicotine, including more than a third of all men over age fifteen. In the United States the smoking rate has decreased to 20 percent of adults, but smoking still kills 480,000 Americans each year, nearly five times as many as alcohol.4

  The toll extends far beyond users. Some people recall bringing friends home after school to find a parent drunk and half-naked. Others’ lives were changed when a father crashed his car into a tree and was never able to talk right or hold a job again. What would it be like at age eight to wonder, every night, if your father was going to wander into your room and possibly hit you, possibly fondle you, or possibly just ramble on, insisting on close attention? What would it be like to listen to your parents screaming and threatening to kill each other in the night and wake to hear them deny that anything had happened? And what do you do when your roommate tokes up every day, stops working, won’t pay rent, and won’t move out?

  Old Questions, New Questions

  The enormity of substance abuse problems has spurred gigantic efforts to find solutions. Most have asked the usual questions: Why do some people get addicted when others don’t? What brain mechanisms cause substance abuse? What strategies for prevention and treatment work best? Plenty of knowledge is now available, but it hasn’t done much to stem the tide.

  Our questions are different, as always.5 Why are members of our species vulnerable to addiction? Drug, alcohol, and tobacco use cause so much early death, you would think that natural selection would have eliminated the alleles that make some people more vulnerable. But it didn’t. Why not? Even aside from natural selection, you would think that people would learn about the dangers of substance use and avoid it. Some do, but most don’t.

  The root cause of the addiction is our capacity for learning.6 Eliminate learning, and you eliminate substance abuse. That is not a practical solution. Learning is useful. It gives advantages that rigid preprograming can’t. Reinforcement learning works by selection—not natural selection but selection among varying behaviors. Individuals do various things. Actions that are followed by rewards become more frequent. Those that fail or cause pain become less frequent.

  There are half a dozen ways to pry the shell off a pistachio nut. Those that break fingernails or leave shells intact are set aside; those that work are repeated and refined. To get fruit from a tree, you can climb up, use a stick, throw a stone, or shake the tree. Whatever works best will be repeated. There are also many ways to entice a potential lover. Whatever works induces a powerful dopamine surge that brings pleasure and a tendency to do it again. Orgasms are powerful reinforcers. Students learn about rats in Skinner boxes and get the idea that learning mechanisms are crude, as if giving people M&M’s can cure problems. However, facial expressions, touches, and tones of voice are also reinforcers. Even the tone you get from a clarinet can shape your mouth to make it better. Tiny blips of dopamine gradually pin a coherent version of a sentence to the page.

  Hijacked

  When the behavior control system operates normally, millions of neurons process dozens of auditory, visual, touch, flavor, and odor cues. If the buzzing electrical pattern in the brain is like patterns that have increased fitness previously, for our ancestors or for the individual, then dopamine blips motivate repeating whatever behavior preceded getting into that good space.

  Drugs that increase or imitate dopamine hijack these subtle mechanisms like a terrorist in a pilot’s uniform taking over an airplane cockpit.7 They bypass brain navigation systems and grab the joystick. Cues present just before the drug reached the control center become enticing. Drug users move toward them, and after arriving, they repeat whatever behaviors worked before to get the reward. That cold, dingy room thick with smoke swirling around a single lightbulb has little appeal—unless you shot heroin there. In which case you will be drawn back to the room, and when you get there you will again almost certainly insert the needle that induced a dopamine surge that signaled to your brain that your fitness just increased by the equivalent of having sixteen grandchildren.

  The pursuit of normal rewards is automatically regulated. Eating is pleasurable at first, but satiation eventually makes even one more Thin Mint unthinkable. Sex has a wonderful conclusion that downregulates desire for a time. The pleasures of social intercourse last longer, but after a while interest declines and shifts behavior elsewhere. Selection never shaped similar systems to control drug taking. Drugs arouse pleasure, causing increased desire and increased drug use, in a vicious spiral down to death.

  None of this was much of a problem for our ancestors. Pure drugs were not reliably available, so they caused no harm that would shape protective systems. That suggests another solution for addiction: turn back the clock ten thousand years, to before the age of agriculture, before pure drugs were available. That is about as practical as eliminating learning. However, substance abuse is a dramatic example of a disease caused by the mismatch between our ancestral brains and our modern environments.

  New techniques of drug purification, new routes of administration, such as cigarette papers and hypodermic needles, and new technologies of transport and storage combine with market economies to ensure availability. Laws and police efforts hardly make a dent. Markets emerge to provide what people want, and technologies adapt to changing situations. Interdiction efforts motivate chemists to invent new addictive molecules, ever more potent and easier to smuggle.

  Why Plants Make Drugs

  Addictive chemi
cals were present long before chemists, thanks to plants. Why do plants make psychotropic drugs? Not for our pleasure, that’s for sure. Cocaine, opium, caffeine, hallucinogens, and nicotine are neurotoxins. Natural selection shaped them because plants containing insect toxins are less likely to be eaten. Few insects can eat a tobacco leaf. Nicotine is such an effective insecticide that a spray of tobacco-infused water protects fruit tree leaves. Caffeine seems innocuous, but a single coffee bean can kill a mouse.

  Most chemicals that give humans a buzz evolved to disrupt insect nervous systems. If our brains used different chemicals, we would not be so vulnerable. However, we have common ancestors with insects. It was long ago, about 500 million years ago, when our ancestors split off from the arthropod lines that became modern insects. However, our neurochemicals remain about the same as theirs. Fortunately, most plant neurotoxins don’t kill us. We have evolved to eat plants, and we are much larger than insects, so low doses are not fatal. But drugs can hijack our motivation mechanisms and take control of our lives.

  Some psychologists have suggested that natural selection shaped us to like drugs and alcohol.8,9 Some such proposals deserve consideration; others strain credulity. For instance, some have wondered if people who liked alcohol might have been more likely to loosen up and have sex, directly increasing fitness. That strikes me as an idea hatched by psychology students getting drunk and hopeful at a pickup bar. Would a tendency to disinhibition give similar reproductive advantages in the ancestral human social environment? I doubt it, but social drug use is common in hunter-gatherer societies, so it is hard to say for sure.

  A taste for alcohol, beer in particular, has been said to decrease the risk of infection because fermented beverages are less likely than water to carry bacteria. The idea makes a fine meme, but it gets little support from history or science.10 A better idea is that alcohol in overripe fruit signals available nutrition.11 This is plausible, but it is also possible that alcohol’s influence on reward mechanisms is an accidental side effect.12 Whatever the reason, people love booze, and some of the most ancient pots discovered by archeologists have residues from fermentation. One can even make a case for people settling down to the boring work of agriculture in part to get reliable access to grain they could use to make beer.13

  Our preference for tobacco could have been shaped because nicotine is a good deworming agent; it paralyzes helminths so they lose their grip on our intestines and are expelled.14,15,16 If this is correct, you would expect tobacco to be used mainly in locations where worms are prevalent, mainly by people with high burdens of worms and mainly orally instead of by smoking. However, diverse species are vulnerable to nicotine addiction; only a few animals in the wild use nicotine-containing plants, and humans don’t usually eat those plants.

  People living in the Andes have chewed coca leaves for centuries. Especially at high altitudes, it relieves fatigue and gives energy for physical work. But I don’t know of evidence that people were shaped to like cocaine. It powerfully reinforces behavior for most animals, not just humans.17

  This is not to say that humans have not influenced plants because of their drugs. We like them so much that we have bred—selected for—tobacco with a high nicotine concentration and marijuana with a high THC concentration. We plant thousands of acres of tobacco, marijuana, coca, and poppies, giving these domesticated species a big advantage over similar plants that don’t offer the same kick. Edward Hagen and his colleagues have suggested that humans have used and benefited from plant psychoactive chemicals long enough for protection against their toxic effects to evolve.18,19,20

  An Old Problem Escalating

  Substance use isn’t new. Neither are its problems. Two anthropologist friends, Paul Turke and Laura Betzig, did field research on a small atoll in the Pacific.21

  The men who live there work a few hours a day fishing with nets. They also make wine by cutting off the tips of young palm trees and bending them over with a string so that the sap drips into a pot. A few days later they return to collect a fermented beverage that gives everyone a good time during evening parties. Pots and string to make palm wine are early drug paraphernalia. Every advance in technology is used to provide ever purer drugs by ever more direct routes of administration.

  Fermentation is easy. Distillation is harder, but the necessary knowledge and equipment are now available almost everywhere. The resulting hard liquor is far more prone to cause addiction. Even without addiction, drunks can be dangerous. Trying to control them has been a function and challenge for governments and policing from the beginnings of written records.

  Tobacco provides a mild high when chewed and more when smoked in cigars. But the addiction that kills more people than any other was initiated when cigarette papers and mild tobacco allowed deep inhalation that gets nicotine to the brain instantly.

  Marijuana is relaxing in the doses available from wild-growing plants. Concentrations have been increased manyfold by breeding and more yet by extracting potent THC concentrates that give hallucinations instead of a gentle high.

  Coca leaves have been chewed for centuries as an energizer, but cocaine was first extracted in the mid-1800s. Its use in beverages and tonics grew so fast at the start of the twentieth century that laws were soon passed to control it, not so much because of addiction but because users were likely to get out of control.22 Freud was a cocaine user, along with many others in the nineteenth century.23 But the problems then were nothing compared to the epidemic in the 1980s that followed the widespread availability of crack, the crystallized form of cocaine.

  Natural opium is addictive when smoked and was a chronic problem in India and China even before new trade routes brought it to Europe in the 1600s. Soon after that, the British East India Company was selling Indian opium in China.24 The Chinese government tried to ban it in 1799. In 1839, the British sent warships to defend their opium business in China. The active ingredient, morphine, is more addictive. A process to extract it was discovered in 1804, and morphine was first marketed by Merck in 1827. Sales soared after the invention of hypodermic needles in the middle of the nineteenth century. Heroin was marketed by the Bayer Company early in the twentieth century as a nonaddicting form of morphine. Whoops! The Harrison Act of 1914 imposed restrictions, and heroin was banned in the United States in the 1920s, but the trade and addiction continue unabated.25,26

  The trajectory is clear: our minds have always been vulnerable to capture by alcohol, marijuana, tobacco, coca, and opium, but problems with them have escalated as advances in chemistry, transportation, and technology have increased the diversity, purity, and availability of drugs. The mismatch was bad before; now it’s getting much worse.

  Some drugs, such as amphetamine, are synthetic from the start, but their effects result from their similarity to neurotransmitters. The rise of easy-to-synthesize methamphetamine has combined with intravenous administration to create a plague that paralyzes whole countries.27 The invention of new superpotent synthetic narcotics makes interdiction efforts nearly hopeless. Carfentanil is ten thousand times more potent than morphine.28 Touching it can cause a fatal overdose, so police now need to wear gloves when making drug arrests. One smuggled printer cartridge can contain a million doses.29 Imagine being the worker who stirs it with powdered milk to dilute it to the right concentration. Slightly inadequate stirring leaves pockets with higher concentrations that will turn into pockets of overdose deaths in the surrounding community.

  Withdrawal, Wanting, and Liking

  When I first learned about substance abuse, the emphasis was on withdrawal. That is what doctors mainly need to manage; however, this focus left the misimpression that people continue to use drugs mainly to avoid withdrawal. Withdrawal is painful, but learning sustains use even without withdrawal.

  Withdrawal syndromes reflect a normal useful regulatory process. Continued stimulation of bodily systems results in opposing shifts that stabilize them. The mellow calm after seve
ral evening drinks is countered by arousal at 3 a.m. The excitement and energy induced by amphetamines crash into depression and fatigue a few hours later. Taking fast-acting antianxiety drugs for a few months downregulates the arousal system. When they are stopped suddenly, compensating systems push anxiety levels sky-high. In the years when we psychiatrists were assured by the highest authorities that it was not habit forming, I started many patients on Xanax. The distress many experienced while getting off the drug still makes me feel guilty and stupid for naively trusting experts who turned out to be shills for pharmaceutical companies.

  Behavior regulation systems use carefully controlled bursts of positive feedback to shift behavior from one activity to another. Reward for the previous activity plummets while reward for the new one escalates. Supercues, of the sort found in modern environments, can hijack such systems. A potato chip advertisement challenges, “Betcha can’t eat just one.” The company wins the bet; our diets lose.

  Most bouts of activity follow a predictable cycle. Once we start an activity, we continue until we are finished, and woe to anyone who interferes. It’s easier to put down the newspaper than a bag of potato chips. And it’s much easier to put down a bag of potato chips than to stop in the middle of making love. As for snorting cocaine . . . Whatever the activity, it tends to rev up at the beginning in ways that make it hard to stop.

  Why do our behavior regulation mechanisms structure our activities into discrete bouts? The proximate explanation is found in brain mechanisms. The evolutionary reason is that most behaviors have start-up costs. They are like the time spent looking for another raspberry bush. Imagine if you picked berries for five minutes, then went out to build a fence, then talked with friends, and then came back and picked berries for another five minutes. At the end of the day, you would be undernourished, the fence would be unfinished, and your friends would likely be very annoyed.