This paper selectively reviews the author’s recent studies on suicidal behaviour in depression. Data are reviewed from a study of depressed patients who had monoamine metabolites measured in both the cerebrospinal fluid (CSF) & urine. Depressed patients who had attempted suicide had significantly reduced CSF concentrations of the dopamine metabolite homovanillic acid & significantly lower urinary outputs of HVA than patients who had not attempted suicide. (13 refs.)