Platelet affinity for serotonin is increased in alcoholics and former alcoholics: a biological marker for dependence?

The kinetics of 3H serotonin platelet uptake were studied in alcoholics and former alcoholics to see whether differences found between alcohol-preferring and non-preferring rats could be reproduced in man. Three groups of patients were studied: 10 dependent alcoholics on admission for treatment; 10 dependent alcoholics after 20 days of treatment; 8 former dependent alcoholics, abstinent for 1-11 years. Controls were non-alcoholics, matched for age and sex. The Km for 3H serotonin uptake in platelets was lower in patients from all three groups compared to 15 controls. This phenomenon could be congenital or induced by the previous excessive intake of alcohol. We believe that this increased platelet affinity for serotonin, in the absence of cirrhosis of the liver and/or depression could be a marker for alcohol dependence, enabling the therapeutic effort to be focussed on these patients.