As director of the National Institute on Drug Abuse (NIDA), Alan Leshner toured the country with a PowerPoint presentation featuring brain scans. The show was a slightly more sophisticated version of the Partnership for a Drug-Free America's famous ad showing an egg frying in a pan. As he flashed magnetic resonance images (MRIs) on a screen, Leshner would say, in effect, "This is your brain on drugs."
Leshner's message was threefold. First, certain drugs are inherently addictive. Second, scientists have discovered the neurochemical processes through which these drugs cause addiction. Third, that understanding will make it possible to develop drugs that cure or prevent addiction. Leshner's traveling PowerPoint show epitomized NIDA's reductionist approach to drug abuse: Take a brain, add a chemical, and voilà, you've got substance dependence.
Leshner left NIDA at the end of November. Coincidentally, Enoch Gordis, head of the National Institute on Alcohol Abuse and Alcoholism (NIAAA) since 1986, retired around the same time. Like Leshner, Gordis sees addiction as a biological problem with a pharmaceutical solution. He believes scientists have "the ability based on new knowledge from neuroscience research to develop pharmacologic treatments that act on brain mechanisms involved in alcohol dependence."
The view of addiction espoused by Leshner and Gordis is at odds with what we know about the actual behavior of drug users and drinkers -- including evidence from government-sponsored research. These studies indicate that treatment is neither necessary nor sufficient for overcoming addiction. The main factor in successful resolution of a drug or alcohol problem is the ability to find rewards in ordinary existence and to form caring relationships with people who are not addicts. By looking instead for a magical elixir just over the horizon, NIDA and the NIAAA give short shrift to the individual circumstances that are crucial to understanding why some people abuse drugs.
'A Medical Illness'
NIDA's official mission is, in its own words, "to lead the Nation in bringing the power of science to bear on drug abuse and addiction." Leshner, who has a Ph.D. in physiological psychology, took the agency's helm in 1994. During his tenure NIDA's budget doubled to $781 million, money devoted mainly to biological research that approaches addiction as a disease.
Although drug use "begins with a voluntary behavior," Leshner said in a 2001 interview with The Journal of the American Medical Association, it ceases to be voluntary after it repeatedly affects the "pathway deep within the brain" common to all drug addiction. "There's no question it's a medical illness," he said, "and once you have it, it mandates treatment. It's a myth that millions of people get better by themselves."
Leshner's model of addiction emphasizes the special power of drugs. After all, he did not travel around the country with MRI images showing how shopping, gambling, or eating potato chips affects the brain. Thus it was startling to see him concede that drug abuse may be fundamentally similar to excessive involvements with other activities that give pleasure or relieve stress. "Over the past 6 months," he said in the November 2 issue of Science, "more and more people have been thinking that, contrary to earlier views, there is a commonality between substance addictions and other compulsions." Some of us have been making this point for years, and it does not fit very well with the idea that drugs create addicts by transforming their brains.
As evidence for this view, Leshner would point to MRI scans of experienced drug users, which he claimed differed in characteristic ways from images of ordinary brains. He also cited studies of drug-induced brain changes in animals. He liked to display a map -- reminiscent of a phrenology chart -- showing which areas of the brain are involved in drug use and addiction.
But Leshner's seemingly scientific claims have never jibed with reality. Consider what the sociologist Lee Robins and the psychiatrist John Helzer found when they headed a team that interviewed veterans who had been addicted to heroin in Vietnam. Only one in eight became readdicted at any time during the three years after they came home. This was not because the rest were abstinent: Six in 10 used a narcotic after returning to the U.S., and a quarter of the previously addicted men used heroin regularly.
Yet only one in five of those who used a narcotic after they got home, including only half of those who used heroin regularly, became readdicted.
The Vietnam situation, of course, was unique. Young men were torn from their homes, sent to a strange and dangerous environment, and offered easy access to heroin. Then they returned to normal life. Still, the results surprised Robins and her associates, who commented: "It is uncomfortable presenting results that differ so much from clinical experience with addicts in treatment. But one should not too readily assume that differences are due to our special sample. After all, when veterans used heroin in the United States...only one in six came to treatment." In other words, looking only at addicts who are treated provides a skewed view of addiction. Indeed, the vets who were treated after they got home actually were more likely to pick up the habit again.
Rats vs. People
Any doubts about the relevance of the Vietnam veterans study are allayed by findings from long-term studies of drug users in the U.S. Long-term cocaine users, for example, generally do not become addicts. And when they do go through periods of abuse, they typically cut back or quit on their own. They may not do so as rapidly as others (and they themselves) wish they would. But addicts act very much like other human beings:
They pursue pleasure or relief, and most will change their behavior when it causes them serious harm, so long as they have reasonable alternatives.