Platelet serotonin content correlates inversely with life history of aggression in personality-disordered subjects

The objective of this study was to test the hypothesis that platelet serotonin (5-hydroxytryptamine, 5-HT) content is correlated with measures of aggression in healthy human subjects. Platelet 5-HT content (ng/mg protein) was measured in personality-disordered (PD) and normal control (NC) subjects. Aggression was assessed with the Life History of Aggression (LHA), the Buss-Durkee Hostility Inventory (BDHI), and the Motor Aggression and Research Criteria for Intermittent Explosive Disorder (IED-IR); impulsivity was assessed with the Eysenck Personality Questionnaire II (EPQII) and the Barratt Impulsiveness Scale (BIS-11). LHA Aggression, but not impulsivity, scores showed significant inverse correlations with platelet 5-HT content in all subjects or in PD subjects alone. The findings in PD subjects remained significant after co-varying for race. PD subjects with IED-IR had lower platelet 5-HT content compared with PD subjects who did not have IED-IR, although this finding only approached significance after controlling for race. This study demonstrates an association between reduced platelet 5-HT content and aggression in PD subjects. Similar to other studies of platelet 5-HT markers, these data suggest that platelet 5-HT content may also reflect central 5-HT alterations and may be used as a biological marker in appropriate patient samples.