The impact of depression and antidepressant treatment on motor function of patients with idiopathic Parkinson's disease

Background

Depression affects approximately 40% of patients with Parkinson's disease (PD). We aimed to evaluate the impact of depression on motor function of patients with idiopathic Parkinson's disease (IPD).

Material and Methods

Thirty-two IPD patients with major depression (IPD-D) were matched for age, sex, age of disease onset and duration of disease with 32 non-depressed IPD patients (IPD-ND). Depression was diagnosed using the Structured Clinical Interview for DSM-IV Axis I Disorders (SCID-I). The Unified Parkinson's Disease Rating Scale (UPDRS) was completed during clinical examination. Motor function was evaluated using the sum of items scores related with tremor, rigidity, bradykinesia and axial impairment, as well as the motor UPDRS subscale score (UPDRSm).

Results

The mean UPDRSm score was significantly higher in the IPD-D group compared with the IPD-ND group (33.7 ± 18.8 vs 22.7 ± 18.3, p = 0.01). Rest tremor and rigidity did not differ between groups. Within the IPD-D group, patients not receiving antidepressant therapy scored higher in the UPDRSm, and had more bradykinesia and axial impairment compared with their matched controls, whereas patients receiving antidepressant therapy showed no difference in the motor function compared with their matched controls.

Discussion

Idiopathic Parkinson's disease patients with major depression had worse motor function compared with those with no depression. Depressed IPD patients receiving antidepressant treatment showed no difference in motor function compared with non-depressed IPD patients. Therefore, we suggest that all PD patients should be evaluated for depression and commence antidepressant treatment if indicated.