Downey's Downfall

If anyone ever had good reason to say no to drugs, it was surely Robert Downey Jr. The actor, 35, had already seen a promising career held back by substance abuse. He had been separated from his wife and son and lost his freedom--twice. But since his release from prison last August, Downey seemed to be turning his life around. He was in the middle of a ratings-boosting guest run as Calista Flockhart's romantic interest on Ally McBeal. He was set to star in a film with Julia Roberts and Billy Crystal and to take a turn onstage in Mel Gibson's production of Hamlet. He had proclaimed in one interview after another that he was ready to put drugs behind him.

Not ready enough, evidently. On Nov. 25, Downey was arrested at a luxury resort in Palm Springs, Calif., charged with possession of cocaine and speed and with violating the terms of his August parole. Against all logic and common sense, he had played with the same fire that had repeatedly burned him in the past--and this time his career could be put on hold indefinitely.

Yet crazy as Downey's latest bout of self-destructive behavior seemed, it was pretty typical for someone who is addicted to drugs or alcohol. Experts and addicts alike have long understood that willpower alone is helpless in the face of addiction, and in recent years science has started to figure out why. "The brain of a drug user," explains Dr. Alan Leshner, director of the National Institute on Drug Abuse, "is physically altered in ways that make it difficult to resist further use."

For public figures like Downey, the danger is especially great. "When you're famous," says Niki Moyer, a psychologist and clinical specialist at the Hazelden Foundation in Center City, Minn., "people respond to your public image, not to you as an individual. But direct human connection is an important key to healthy recovery." Going public with declarations that you're on the wagon, as Downey did in Vanity Fair and other publications, doesn't help. The feeling that your struggle is on full public view adds stress that can help trigger a relapse. That's one reason, says Moyer, that the Alcoholics Anonymous 12-step program and others like it counsel against self-disclosure to the media.

But ultimately, addiction is a physical disease of the brain caused by exposure to drugs. It starts, many neuroscientists believe, when alcohol, cocaine, amphetamines or other drugs boost the activity of a brain chemical called dopamine, which generates the sensation of pleasure. Flip the pleasure switch often enough, and nerve cells in many parts of the brain--especially in a tiny region known as the nucleus accumbens--become accustomed to the rush. When the switch is left in the off position too long, nerve cells feel deprived, a sensation the addict experiences as a nearly irresistible craving.

That craving can be staved off by substitute drugs--methadone for heroin, for example. But while doctors have found substitutes for nicotine and alcohol, there's nothing yet for cocaine and amphetamines. The craving can also be diverted through behavior-modification therapy and by regular participation in self-help groups like Narcotics Anonymous.