The neurotransmitter metabolites 5-hydroxyindoleacetic acid (5-HIAA), homovanillic acid (HVA) & 4-hydroxy-3-methoxyphenyl glycol (HMPG) were measured by mass fragmentography in 83 patients with melanchol, & 66 healthy controls. Significantly lower levels of 5-HIAA & HVA were found in the melancholia patients. The reduced concentrations of 5-HIAA & HVA in the melancholic patients may be due to altered serotonin &/or dopamine functions in the CNS. 82 Ref.