Impaired reward sensitivity in Parkinson's depression is unresponsive to dopamine treatment.

Interestingly, however, when restricting this analysis to depressed participants (with and without PD) and covarying for group, anhedonia symptom severity narrowly missed significance (DARS: β = 5.4, 95%CI −0.41 to 11, P = 0.068), suggesting specifically depressed patients with more severe anhedonia may subjectively perceive rewards as less valuable.

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