SUICIDALITY, CIRCADIAN ACTIVITY RHYTHMS AND PLATELET SEROTONERGIC MEASURES IN PATIENTS WITH RECURRENT SUICIDAL-BEHAVIOR

The circadian activity rhythm was assessed over a one-week period usin g a wrist-worn activity monitor in 59 patients with a history of recur rent suicide attempts. In 40 of these patients a second recording was made 6 months later. Platelet serotonin (5-HT) and monoamine oxidase-B activity (MAO) were measured. Suicidal ideation, borderline personali ty disorder and impulsiveness were associated with the absence of a cl ear 24-hour periodicity in motor activity. Depressive mood and hopeles sness were associated with a less regular bed-in time and a lower dayt ime activity. Platelet 5-HT as well as MAO correlated negatively with the amplitude of the circadian activity rhythm. Our results support th e suggested link between suicidality, altered circadian activity and s erotonergic function.