Platelet MAO Activity and Monoamine Metabolites in Cerebrospinal Fluid in Depressed and Suicidal Patients and in Healthy Controls

Platelet monoamine oxidase (MAO) activity & cerebrospinal fluid (CSF) concentrations of 5-hydroxyindoleacetic acid (5HIAA), homovanillic acid (HVA), & 4-hydroxy-3-methoxyphenylglycol (HMPG) were simultaneously measured in 20 currently depressed patients, 11 recovered depressed patients, 15 nondepressed suicide attempters, & 42 control subjects. Both 5HIAA & HVA were positively & significantly correlated to platelet MAO activity in the healthy subjects. Suicide attempters had lower CSF 5HIAA.