Neurotransmitters May Be Key to Treating Alcoholism
Rodgers, Katie, Drug Topics
Despite the fact that 15.3 million Americans suffer from alcohol abuse or alcohol dependence, pharmacological treatment for the nation's No. 1 addictive disorder is limited to disulfiram (Antabuse), a 40-year old agent with a varying success rate. But recent breakthroughs in the understanding of the neuroscientific aspects of alcoholism have opened doors to the discovery of new pharmacologic therapies. The National Institutes of Health is currently funding 21 studies on drugs for the treatment of alcoholism.
In an interview with Drug Topics, Raye Z. Litten, Ph.D., a scientist at the Treatment Research Branch of the National Institute on Alcohol Abuse & Alcoholism, discussed new strategies in alcoholism research and the role of neurotransmitters in the pathogenesis and treatment of the disorder.
"Over the past 10 years, there have been some advances made, at a neuroscience level, in understanding why people drink," Litten said. "Neurotransmitter systems, such as the opiate system, serotonin, dopamine, and the GABA system, appear to be involved either directly or indirectly." Studies in animals have shown that low doses of morphine cause rats to increase alcohol consumption while opioid antagonists decrease alcohol intake.
According to Litten, one promising drug for the treatment of alcoholism is naltrexone, an opioid antagonist currently used for narcotic dependency. The NIH is now funding nine studies to assess how effective this drug is for the treatment of alcoholism and trying to elucidate its mechanism of action in alcoholic patients, Litten said.
Two independent studies have shown that when used in addition to psychosocial interventions, treatment with naltrexone decreased alcohol craving, decreased the number of drinking days, and cut down on the number of relapses. In patients who did relapse, there was less tendency to continue to drink. "It seemed that naltrexone blocked the reinforcing effects of alcohol," Litten said. Although not well understood, opioid antagonists may exert their effect in the treatment of alcoholism by preventing alcohol's activation of endogenous peptides.
Litten said the encouraging results of these studies raise even more questions about the role of neurotransmitters in the treatment of alcoholism: "Can these results be reproduced in other settings? …