Monoamine interactions in narcolepsy and hypersomnia: a preliminary report

Principal component analysis was performed on data obtained for the concentrations of 3,4-dihydroxyphenylacetic acid, 3-methoxy-4-hydroxyphenylethylene glycol, homovanillic acid, and 5-hydroxyindoleacetic acid in lumbar cerebrospinal fluid from a group of normal volunteers (n = 40), hypersomniac patients (n = 13), and narcoleptic patients (n = 8). All four compounds were shown to be highly intercorrelated in the normal volunteers. In the hypersomniac patients, 3-methoxy-4-hydroxyphenylethylene glycol did not appear to be correlated with the other three compounds. In the narcoleptic patients, homovanillic acid and 3,4-dihydroxyphenylacetic acid appeared not to be correlated with the other two metabolites. The results provide tentative support for a neurochemical distinction between narcolepsy and hypersomnia and suggest that attention should be given to a possible malfunction of the dopamine system in narcolepsy and norepinephrine in hypersomnia.