CSF monoamine metabolites of depressed patients during illness and after recovery.

Repeated lumbar punctures in 16 healthy volunteers showed reproducible concentrations of 5-hydroxyindoleacetic acid (5-HIAA) and homovanillic acid (HVA) in cerebrospinal fluid (CSF). In seven depressed patients, studied during two or three illness periods, the metabolite concentrations were also fairly stable. In 11 patients CSF concentrations of 5-HIAA, but not of HVA, were higher after recovery than during depression. This increase of 5-HIAA after recovery was confined to patients whose initial serotonin metabolite levels were low. The finding constitutes further evidence of a biochemical heterogeneity within the depressive disorders, and suggests that patients whose CSF 5-HIAA is low during a depressive episode may have a less stable serotonin system than other patients with depressive illness.