Abstract: Objective The clinical heterogeneity of Parkinson's disease (PD) may point at the existence of subtypes. Aim of this study is to assess the severity of depression in patients with PD of different clinical subtypes. Methods A broad spectrum of motor variables and nonmotor features, including tremor, rigidity, hypokinesia, postural instability gait disorder, fatigue, constipation, apathy, depression, global cognitive function, as well as the clinical data and demographics, including age, gender, age at disease onset, course of disease, were collected in 600 Chinese PD patients. The PD subtypes were classified using k-means (k=4) cluster analysis according to the clinical data. Their depression was assessed with Center for Epidemiologic Studies Depression Scale (CES-D). Results The cluster analysis indicated 4 main subtypes: Subtype 1 was mildly affected in all domains, and the ratio of tremor score to non-tremor score was the highest among the 4 clusters. Subtype 2 was severely in all motor and nonmotor symptoms. Subtype 3 showed intermediate severity in most domains. Subtype 4 was characterized by short course and rapid progression of disease. 43.5% of cases were identified as in depression. There was significant difference in scores of CES-D among the 4 subtypes (P<0.05). Conclusion Depression occurred frequently in patients with PD with some clinical heterogeneity.

Key words: Parkinson's disease, heterogeneity, depression, cluster analysis