Changes in dopamine receptor responsivity during alcohol detoxification may predict relapse.

In the search for clinical and biological variables that may predict relapse of alcohol dependent patients after detoxification, we followed up for 1 year male patients that had undergone successful detoxification. The patients had been tested earlier during their usual alcohol consumption and immediately after detoxification for the responsivity of D2 dopamine receptors (as measured by the increases in prolactin plasma levels caused by intramuscular administration of 5 mg of the dopamine receptor blocker haloperidol). Of the 18 patients, eight had not consumed alcohol for more than 6 months, and ten had relapsed within 6 months. Comparison of the clinical and neuroendocrine data for the two subgroups revealed no significant differences in age, amount of alcohol consumed during alcohol abuse, score in the Beck Depression Inventory, score in the Brief Michigan Alcoholism Screening Test, or prolactin responses to haloperidol before detoxification. In patients who relapsed, the duration of alcoholism was marginally shorter (P=0.055). Patients who did not relapse had significantly higher (P=0.003) prolactin responses to haloperidol in the test performed after detoxification as compared with patients who did relapse, and their responses were similar to those of a group of healthy male subjects. The results show that the increase in dopamine receptor responsivity that occurs after detoxification is a favourable factor for non-relapse; it may reflect recovery from down-regulation of the dopaminergic reward system caused by alcohol consumption.