We studied 99 hospitalized depressed, 14 manic, and 61 healthy control subjects and evaluated relationships during a drug-free baseline period between behavioral measures (postulated to be associated with brain norepinephrine, dopamine, and serotonin function) and metabolites of these neurotransmitters sampled from lumbar cerebrospinal fluid (CSF): 3-methoxy-4-hydroxyphenylglycol (MHPG), homovanillic acid, and 5-hydroxyindoleacetic acid. Depressed subjects with increased anxiety, agitation, somatization, and sleep disturbance were found to have significantly elevated concentrations of CSF MHPG; this relationship was not found in the healthy controls. A correlation between CSF MHPG level and an anxiety/agitation dimension measured in all subjects was statistically significant but explained a modest portion of the total variance. No consistent relationships were found between CSF MHPG and depression/retardation, hostility/interpersonal sensitivity, and global severity, nor did any of these measures correlate significantly with the levels of the other monoamine metabolites, although some trends were found. Other factors did not account for the relationships between CSF MHPG and some behavioral measures, including diagnostic subgroup, motor movement, age, sex, and premenopausal or postmenopausal status in women. Suggested relationships among drug treatment modality, eventual treatment outcome, behavioral and mood state at baseline, and these metabolite levels will require further analyses.