Decreased density of the platelet serotonin transporter in pathological gamblers.

Background/aims: The aim of this study was to investigate the serotonin transporter (SERT), by means of the 3H-paroxetine ([3H]-Par) binding to platelet membranes, in patients affected by pathological gambling (PG), as compared with a similar group of healthy control subjects.

Methods: Seventeen PG patients were selected amongst those who were drug-free and at the first psychiatric interview in a Department of Addiction. The diagnosis was assessed according to DSM-IV criteria and PG severity was measured by means of the South Oaks Gambling Screen. The platelet [3H]-Par binding was carried out according to a standardized method. The binding parameters, the maximum binding capacity (B(max)) and the dissociation constant (K(d)), were obtained by means of the Scatchard analysis.

Results: The B(max) values of PG patients were significantly lower than that of healthy subjects, while the K(d) values were not different in the two groups. No significant effect of age, sex or psychiatric comorbidity on B(max) or K(d) was observed; there were also no correlations between clinical and biological variables.

Conclusions: PG patients showed a dysfunction at the level of the platelet SERT that would suggest the involvement of the 5-HT system in this condition.