PLATELET 5-HT CONCENTRATIONS AND SUICIDAL-BEHAVIOR IN RECURRENT MAJORDEPRESSION

Platelet 5-HT concentrations were determined in 84 male and 82 female psychotic and non-psychotic depressed inpatients with various degrees of suicidal behaviour, and in 175 healthy controls. Psychotic patients had higher platelet 5-HT concentrations than non-psychotic depressed patients and healthy controls. A sex difference, i.e., lower platelet 5-HT concentrations in females was found in healthy controls, depresse d patients, non-psychotic patients and non-suicidal depressed patients . A negative relationship was shown between platelet 5-HT concentratio ns and suicidal behaviour. The lowest platelet 5-HT concentrations wer e associated with the most pronounced suicidal behaviour (with suicida l attempts and with the acts of suicide). The results suggest that the differences in platelet 5-HT concentrations found in depressed patien ts might be used as a biological marker for suicidal behaviour.