Anhedonia in Japanese patients with Parkinson's disease

Anhedonia has been proposed as a specific mood disorder related to the dopaminergic nerve dysfunction seen in Parkinson's disease (PD). This study examined hedonic tone in patients with PD using the Snaith-Hamilton Pleasure Scale (SHAPS) and investigated the associations with depressive mood by the Self-Rating Questionnaire for Depression (SRQ-D).

This study examined 100 patients with PD and 111 age-matched controls (C2) recruited from 300 healthy subjects (C1) to compare the frequency of anhedonia and to clarify whether anhedonia in PD is associated with depression and anti-Parkinson medication.

Forty-six percent of PD patients revealed possible/probable depression and 10 patients (10%) with PD showed anhedonia as compared to 3.3% in C1 and 2.7% in C2. The reduction in hedonic tone was related to depression in PD. Among 10 PD patients with anhedonia, seven were in anhedonia with depression and three were in anhedonia without depression. There was no sex difference in anhedonia and depression. No patients treated with pramipexole showed anhedonia but also the highest proportion of normal hedonic tone was found in patients treated with pramipexole among PD patients. In analysis of each SHAPS item, no significant difference was seen on social interaction scores in contrast to the significant reduction of interest/pastimes and sensory experience and food/drink scores between PD patients and C1/C2.

Anhedonia may overlap depressive syndrome but some PD patients without depression presented anhedonia. Pramipexole could maintain hedonic tone. The PD patients could enjoy attracting attention and wish to do things helpful for others.