Peripheral serotonergic markers in patients with suicidal behavior.

Peripheral serotonergic parameters were studied in 17 patients with a history of suicidal behavior and in 17 age- and sex-matched healthy controls. Serotonin2 receptor function in platelets, measured as serotonin-induced [32P]phosphatidylinositol 4,5-bisphosphate hydrolysis, was significantly higher in patients than in age- and sex-matched controls. Increased serotonin2 receptor transduction was not correlated to psychiatric diagnosis, drug treatment or a history of violent suicide attempt. Monoamine oxidase activity was lower in platelets from patients with a history of suicidal behavior than in controls. In addition, whole blood serotonin was analyzed but no significant alterations were found in blood from patients.