Relationships between clinical symptoms and monoamine metabolite concentrations in biochemically defined subgroups of depressed patients

Abstract

In 28 patients with primary depression, relationships were sought between rating scores on the Montgomery-Asberg Depression Rating Scale and the concentrations of the monoamine metabolites 5-hydroxyindoleacetic acid (5-HIAA), homovanillic acid (HVA) and 4-hydroxy-3-methoxyphenylglycol (HMPG) in cerebrospinal fluid (CSF). Among the single items in the rating scale, reported sadness correlated negatively with HMPG. No other significant relationships were found in the total group of patients. However, in subgroups with low or high concentrations of monoamine metabolites, several significant relationships were found, such as a negative correlation between inner tension and concentration difficulties, respectively, and 5-HIAA in the low-HMPG subgroup. Curvilinear relationships were found between pessimistic thoughts and 5-HIAA in the high-5-HIAA subgroup and between apparent sadness and 5-HIAA in the low-HMPG subgroup. Suicidal thoughts tended to correlate in a curvilinear way with the ratio of HMPG/5-HIAA in the low-HVA and the high-HMPG subgroups, but the curves were mirrored. The results indicate that relationships between clinical symptoms and monoamine metabolite homeostasis in CSF are qualitatively and quantitatively different in defined high-and low-monoamine subgroups of depressed patients.