The relationship of serotonin to depression in Parkinson's disease.
We have previously reported a correlation between depression in patients with idiopathic Parkinson's disease and decreased concentrations of the cerebrospinal fluid content of the serotonin metabolite, 5-HIAA. To further examine this relationship, we repeated the study in a new cohort of patients while they remained on dopaminergic medications, conducted follow-up interviews and examinations in our original cohort, and conducted an open trial of the serotonin precursor, 5-hydroxytryptophan in a group of new patients with depression. We were again able to demonstrate a significant reduction in cerebrospinal 5-HIAA in depressed patients in comparison to controls and patients without depression. Demented patients with Parkinson's disease, particularly those with concurrent depression, had the lowest values of 5-HIAA. No new cases of depression occurred in our original cohort after 2 1/2 years of follow-up, and depression remitted following conventional or experimental treatment in four patients. Depression improved in six of the seven new patients following oral 5-hydroxytryptophan. Three of these patients allowed a repeat lumbar puncture, and the concentration of 5-HIAA increased following 5-hydroxytryptophan. These three studies support our hypothesis that depression in idiopathic Parkinson's disease is associated with a reduction in brain serotonin. However, it also suggests that other factors, biological or environmental, may be causal factors.
Mayeux
R
R
Department of Neurology, College of Physicians and Surgeons, Columbia University, New York, New York 10032.
Stern
Y
Y
Sano
M
M
Williams
J B
JB
Cote
L J
LJ
D006916:5-Hydroxytryptophan / Q000627:therapeutic use; D000368:Aged; D002986:Clinical Trials as Topic; D003704:Dementia / Q000134:cerebrospinal fluid / Q000150:complications; D003866:Depressive Disorder / Q000134:cerebrospinal fluid / Q000188:drug therapy / Q000209:etiology*; D005260:Female; D006801:Humans; D006897:Hydroxyindoleacetic Acid / Q000134:cerebrospinal fluid; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D010300:Parkinson Disease / Q000150:complications*; D012701:Serotonin / Q000502:physiology*
D012701:Serotonin; D006897:Hydroxyindoleacetic Acid; D006916:5-Hydroxytryptophan