• We carried out a 5-year follow-up study of suicidal behavior among depressed patients who earlier had determinations of cerebrospinal fluid levels of monoamine metabolites. Patients who reattempted suicide during the follow-up had significantly lower cerebrospinal fluid levels of both the serotonin metabolite 5-hydroxyindoleacetic acid and the dopamine metabolite homovanillic acid. The findings were most striking among melancholic patients. These follow-up results suggest that reduced central turnover of serotonin and dopamine may be associated with further suicidal behavior among depressed patients who have previously attempted suicide.
Roy A, De Jong J, Linnoila M. Cerebrospinal Fluid Monoamine Metabolites and Suicidal Behavior in Depressed PatientsA 5-Year Follow-up Study. Arch Gen Psychiatry. 1989;46(7):609–612. doi:10.1001/archpsyc.1989.01810070035005