Animal experiments suggest that endogenous substances that could result from the interaction between neurotransmitters (dopamine and indoleamines) and ethanol and its metabolite acetaldehyde might be involved in the pathogenesis and maintenance of alcohol dependence. Therefore, aromatic beta-carbolines (norharman and harman) were investigated repeatedly in 24-hr urine of 13 male severe alcoholics without any psychiatric comorbidity during a controlled inpatient abstention program of up to 8 weeks. Harman excretion was similar to 2-fold above levels in control subjects, with a steady decline after 3 weeks of abstinence and lower levels in patients with a longer duration of alcohol dependence, Severity of withdrawal symptoms and actual feelings of anxiety/depression were negatively associated with urinary harman excretion. positive associations could be established with daily ethanol consumption the month before admission and the score on the scale ''reward dependence'' according to Cloninger's Tridimensional personality Questionnaire. Moreover, patients without alcohol-dependent first-degree relatives and higher ''reward dependence'' exhibited an increased excretion of harman. Therefore, barman levels might characterize a distinct subgroup of alcoholic patients, who in part resemble the so-called type I alcoholics of Cloninger. However, this awaits further study in a larger number of individuals. In contrast, norharman excretion was elevated up to 6-fold, compared with nonalcoholics over 6 to 8 weeks of controlled abstention. No correlations to demographic or clinical variables could be observed. Therefore, increased norharman levels might be proposed as a ''residual marker'' or a trait variable. Whether the observed changes are specific markers of at least certain aspects of alcoholism or dependence remain to be elucidated.