Anhedonia in Japanese patients with Parkinson's disease: analysis using the Snaith-Hamilton Pleasure Scale

Anhedonia, a lowered ability to experience physical or social pleasure, has recently been recognized as a non-motor symptom of Parkinson's disease.

To identify the frequency of anhedonia and the factors influencing hedonic tone in Japanese patients with Parkinson's disease.

We recruited 86 consecutive outpatients with a clinical diagnosis of PD attending two Japanese hospitals (one university hospital and one community hospital) in February 2010. We used the self-rating Snaith-Hamilton Pleasure Scale (SHAPS) translated into Japanese language from the original English version to assess and quantify hedonic tone as a subjectively experienced phenomenon. We studied the association of anhedonia with the variables age, age at onset, gender, disease duration, disease severity and antiparkinsonian drugs.

Thirty-nine patients (45%) were male and 47 (55%) were female. Mean age was 72.01±9.07 (49-89) years, with mean age at onset of 64.93±11.42 (31-88) years. Mean disease duration was 7.20±5.54 (1-23) years. The mean Hoehn and Yahr scale was 2.76±0.78. The mean SHAPS score of the total sample was 1.19±1.86. The SHAPS score of 14 patients (16.3%) was 3 or more, indicating anhedonia. The mean SHAPS score was lower in patients taking pramipexole (0.58±0.97) than in patients not taking pramipexole (1.57±2.16). Multiple linear regression analysis identified pramipexole as a significant negative influencing factor on the SHAPS score, while disease severity and entacapone treatment were identified as positive influencing factors. The age, onset age, gender, disease duration, and use of pergolide, amantadine, zonisamide, selegiline, anticholinergic agents and droxidopa did not significantly affect the SHAPS score.

Anhedonia is not rare non-motor symptom in Japanese patients with Parkinson's disease. This study suggests an anti-anhedonic property of pramipexole.