Depression in Parkinson's disease

Objective

The current study estimated the cognitive impairment in depressed patients with Parkinson's disease (PD) and the interference on activity of daily living and quality of life.

Method

The study included a series of 26 PD patients with major depression, 16 PD patients with dystimic disorder, and 38 nondepressed PD patients. Also 37 neurologically healthy control subjects matched by age, gender and education were included in the study. Comprehensive psychiatric evaluations including the Structured Clinical Interview for DSM-IV and depression rating scales Hamilton Rating Scale for Depression (HDS) and Beck's Depression Inventory (BDI) were administered. The cognitive evaluation included the comprehensive classical and automated neuropsychological tests. All patients were rated on the Unified Parkinson Disease Rating Scale (UPDRS)-Activities of Daily Living (ADL) subscore. As a measure for self-evaluated emotional functional and social dimensions of health Parkinson Disease Questionnaire–39 (PDQ)–39 was applied.

Results

The executive and memory deficits are still present in major depressed PD group, even when the host of confounding variables like age, education, gender, age at onset of the disease, disease duration, disease severity, motor slowness, medication and general cognitive abilities. The major depressed PD patients were significantly more physically disabled than those with no depression in terms of ADL scores, and lower Quality of Life scale scores. In the presence of no difference in the disease duration between different PD groups, this corresponds to more rapid disease progression in major depressed PD group. The cognitive functioning, depression severity and motor slowness strongly interfere with the activities of daily living and overall quality of life in depressed PD patients.

Conclusions

These findings provide evidence that the more profound cognitive deficits in PD depressed patients are mainly due to depression. Also, faster disease progression, greater functional disability and low quality of life are hallmarks for the PD with depression. Treatment of depression may ameliorate aspects of cognitive and functional dysfunction in the PD with depression.