Hedonic and behavioral deficits associated with apathy in Parkinson's disease: Potential treatment implications

Background: Many individuals with Parkinson's disease (PD) experience apathy independent of depression. Methods: In this study, we examined hedonic and behavioral deficits related to apathy in 50 patients with PD and 42 healthy older adults who completed standardized measures. Results: Regression analyses revealed that apathy was associated with anticipatory, but not consummatory, anhedonia and reduced goal-directed behavior, independent of PD diagnosis, age, education, and depressive symptoms. Conclusions: These findings suggest that apathy is characterized by deficits in anticipatory pleasure and behavioral drive rather than consummatory pleasure or reward responsiveness. Therefore, PD patients with apathy would likely benefit from psychotherapeutic treatment that encourages structured, goal-directed plans for pleasurable events and stimulation that provide adaptive hedonic effects. In addition, given the proposed shared mechanism of dopamine depletion within the ventral striatum in apathy and anticipatory anhedonia, future trials of dopamine-eliciting activities (eg, exercise and other nonpharmacologic methods) appear to be warranted to improve these symptoms in patients with PD. (c) 2013 Movement Disorder Society