Variations in CSF monoamine metabolites according to the season of birth.

The cerebrospinal fluid (CSF) concentrations of the monoamine metabolites 5-hydroxyindoleacetic acid (5-HIAA), homovanillic acid (HVA) and 3-methoxy-4-hydroxyphenylglycol (MHPG) as well as their ratios and correlations were analyzed in relation to the season of birth. The sample consisted of 241 drug-free patients participating in psychobiological programs and comprising the DSM-III-R diagnoses of mood, anxiety and adjustment disorders. Significant season-of-birth variations were found even after adjusting for sex, age, height, the diagnostic category and the month of lumbar puncture. Those born during February to April had significantly lower values of 5-HIAA. Values of HVA and of the ratios HVA/5-HIAA and HVA/MHPG were significantly higher for those born during October to January. Correlation coefficients also showed season-of-birth variations. These results may provide an important link for the season-of-birth variations reported for several neuropsychiatric disorders.