Evoked potentials, serotonin, and suicidality.

The link between suicidality and serotonergic dysfunction is a consistent finding in biological psychiatry. In three independent studies we found weak intensity dependence of auditory evoked potentials, which may be related to high serotonergic activity, in psychiatric patients with a history of suicide attempts. This result seems to contradict studies reporting low serotonergic activity in acute suicidal patients. As an explanation for this discrepancy we propose that serotonergic activity may be low only in acute suicidal states, and that high serotonergic activity, as reflected by a weak intensity dependence, may characterize high-risk patients, in whom a transient decrease of serotonergic activity is accompanied by acute suicidality.