Concentrations of 5-hydroxyindoleacetic acid (5-HIAA) in the lumbar CSF
were measured in a group of suicidal schizophrenic patients and in a
matched group of nonsuicidal schizophrenic patients. The suicidal group had
a significantly lower level. This finding is consistent with reports of low
levels of CSF 5-HIAA in suicidal patients with other psychiatric diagnoses
and suggests that low CSF 5-HIAA may be a generalized marker of aggressive
behavior against the self and others.