Apathy and depression in Parkinson's disease: the Belgrade PD study report.

Apathy and depression are among the most common psychiatric and behavioral disorders associated with Parkinson's disease (PD). The objective of this study was to examine the prevalence and demographic and clinical correlates of apathy and depression in a clinical population-based sample of patients with PD and to assess whether apathy may present as a primary behavioral disturbance independent from depression and cognitive impairment. A series of 360 PD patients underwent psychiatric investigation with the Starkstein's Apathy Scale (AS), and the 17-item Hamilton Depression Rating Scale (HDRS-17), motor scoring with Hoehn and Yahr (HY) staging, and the Unified Parkinson's Disease Rating Scale (UPDRS); and cognitive screening with the Mini-Mental State Examination (MMSE) on the same day. Apathy coexisted with depression in 133 (36.9%) of PD patients, compared with depression without apathy in 16 (4.4%), apathy without depression in 84 (23%), and neither apathy nor depression in 127 PD patients (35.2%). Apathy was associated with higher axial UPDRS impairment score, lower MMSE score, higher l-dopa dosage, and earlier HY stages, while depression was predicted by the more advanced HY stages and younger age of PD patients. These findings suggest that apathy and depression may be separable in PD, although both are common in patients with PD. Therefore these two conditions should be systematically screened and considered in the care and management of PD.