ENDORPHINS AND EXPERIMENTAL ADDICTION

Animal studies suggest that the endogenous opioid systems in the brain play an important role in the initiation and maintenance of drug depe ndence. Opioids in the ventral tegmental area (VTA) may be involved in rewarded behaviors and, consequently, in the initiation of drug self- administration that may be associated with addiction proneness. Opioid s in the limbic forebrain are particularly implicated in subsequent dr ug self-administration, which may be associated with craving, maintena nce, and relapse. Alcohol intake in monkeys is reduced after treatment with naltrexone in a graded, dose-dependent manner. Naltrexone also i s associated with a greater decrease in alcohol consumption after impo sed abstinence. These findings support the idea that endorphins play a role in alcohol-drinking behavior, particularly after a period of abs tinence during the so-called catch-up phenomenon. Recent studies of re covering alcoholic patients provide evidence that opiate antagonists a ttenuate the craving for alcohol and decrease and/or postpone relapse into addictive behavior.