Suicidality, Circadian Activity Rhythms and Platelet Serotonergic Measures in Patients With Recurrent Suicidal Behaviour

The circadian activity rhythm was assessed over a 1 week period in 59 patients. Platelet serotonin (5-HT) & monoamine oxidase-B activity (MAO) were measured & found to correlate negatively with the amplitude of the circadian activity rhythm. Suicidal ideation, borderline personality disorder & impulsiveness were associated with the absence of a clear 24-hour periodicity in motor activity. Results support the suggested link between suicidality, altered circadian activity & serotonergic function.