Evidence supporting a cognitive model of depression in Parkinson's disease.

The objective of this study was to explore the possibility that depression in Parkinson disease (PD) arises from an illness-related vulnerability to negative emotional stimuli. The Color-Word and Emotional Stroop tasks were performed by 27 nondepressed patients with PD and 27 healthy volunteers. Patients with PD showed greater interference to the sad words of the Emotional Stroop than did control patients, despite similar performances to the controls on the neutral and Color-Word Stroop tasks. Nondepressed patients with PD may have attentional mechanisms that are vulnerable to negative stimuli. This vulnerability might arise out of a common involvement of anterior cingulate regions in both selective attention and mood regulation, and could in turn predispose to cognitive distortions that may lead to depression.