Medicine: Can Drugs Cure Drug Addiction?

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Other medications being used for psychiatric or neurological conditions are also showing some promise. Flupenthixol, currently prescribed overseas for schizophrenia, seems to soften the "crash," a unique combination of depression and craving that follows one cocaine binge and typically leads to another round. In preliminary trials on a group of ten Bahamian crack addicts seeking treatment, researchers from Yale found that even low doses kept users off cocaine for the two-month duration of the trial. Another drug, carbamazepine, long taken to prevent seizures, has proved to be moderately effective against cocaine craving. In tests this year, six of 13 people taking the drug stopped using cocaine and the remaining seven reduced their intake about two-thirds. Researchers got the idea for using this antiseizure drug after hearing reports that low doses of cocaine triggered mini-seizures in some animal brains and that this "kindling" in the brain might be linked to craving. By next year, NIDA expects to have eight to twelve antiaddiction medications in clinical trials.

Still, scientists are not expecting miracles, particularly in battling cocaine addiction. Unlike heroin, which acts on the pain-killing endorphin system alone, cocaine engages three separate neurotransmitter systems: those based on dopamine, serotonin and norepinephrine. Taken together, these networks govern the human ability to experience pleasure, from watching a sunrise to having sex. Blocking all these pleasure centers -- as methadone blocks the heroin high -- would literally take the joy out of life, says Yale's Kosten. "We'd turn out automatons." Addicts trying to quit cocaine go through a stage called anhedonia, a sort of spiritless limbo that typically drives the user to take the drug again. At best, researchers can hope for a patchwork of drugs to block discrete stages of cocaine withdrawal, such as craving and depression.

It is far from clear that the new drugs will succeed even in this limited way. None have been tested in a full-scale trial designed to mimic the conditions addicts encounter on the street. Buprenorphine, which is one of the furthest along in testing, is unlikely to receive approval before 1992. Scientists also readily concede that medical therapy fails to address the underlying psychological and social causes of drug abuse. Even if an addict is weaned from one drug, they say, he will very often take up another. A federal study released in August found that as many as 47% of patients at 15 methadone clinics across the country continued to use heroin or other opiates, and up to 40% used nonopiate drugs, usually cocaine. So scientists find themselves aiming their magic bullet at a moving target. "We're constantly having to treat new disease," said Marvin Snyder, director of NIDA's medications- development program. "In five years, the problem may not be cocaine, but some drug we haven't even heard of."