Platelet serotonin levels in alcoholic patients: changes related to physiological and pathological factors

This study investigated platelet serotonin (5-hydroxytryptamine; 5-HT) levels and the effects of different physiological and pathological factors in 108 alcoholic patients (alcohol abuse, n = 49; alcohol dependence, n = 59) and 32 healthy control subjects. Platelet 5-HT levels were determined by a fluorescent-ortho-phthalaldehyde assay. In patients, platelet 5-HT levels during withdrawal from alcohol and after 2 weeks of abstinence were significantly lower than in control subjects. Among patients, this decrease was enhanced both in alcohol-dependent patients and in patients who were depressed during the withdrawal phase, whereas lifetime impulse control disorders (mostly found in alcohol abusers) were associated with comparatively high platelet 5-HT levels (i.e., close to control subjects' values). These results, which reflect the likely biphasic effect of alcohol ingestion upon 5-HT functioning, are consistent with the dimensional 5-HT hypothesis in psychiatric disorders.