Animal studies and some of thephenomena associated with alcoholism in humans suggest that some central effects of alcohol may involve serotonergic systems. The CSF metabolites of serotonin and dopamine, 5-hydroxyindoleacetic acid (5HIAA), and homovanillic acid (HVA) were studied in hospitalized alcoholics. There were no significant differences in HVA levels between groups. The level of 5HIAA of alcoholics in the abstinence phase, 28 to 63 days after their last drink, was significantly lower (21.8 +/- 1.9 ng/mL) than both a nonalcoholic comparison group (31.7 +/- 2.0 ng/mL) and alcoholics in the immediate postintoxication phase, within one to two days after their last drink (32.3 +/- 2.9 ng/mL).