In a study of 104 patients with Parkinson's disease (PD) and 61 control
subjects with equal disability scores, PD patients had higher depression
scores (P < 0.001) than control subjects. Functional disability was
correlated with depression in PD and, in a regression analysis, explained
9% of the variance in depression (P < 0.001). Depression was not
correlated with novelty seeking, a personality trait related to
dopaminergic pleasure and reward systems. Harm avoidance, a trait related
to central serotonergic systems, was, however, correlated with depression
(P < 0.001) and explained 31% of the variance in depression scores.
Results support the hypotheses that both physiologic and psychologic
factors contribute to depression seen in these patients and that
serotonergic function plays a more critical role than dopaminergic
function.Abstract Teaser