The accuracy of diagnosis of major depression in patients with Parkinson's disease: a comparative study among the UPDRS, the geriatric depression scale and the Beck depression inventory

OBJECTIVE: Evaluate the accuracy of diagnosis of major depression in patients with Parkinson's disease (PD) using the UPDRS, the 15-item Geriatric Depression Scale (GDS15) and the Beck Depression Inventory (BDI). METHOD: 50 consecutive patients with PD were evaluated. The diagnosis of major depression was made according to the DSM-IV criteria. RESULTS: We found a 24% prevalence of major depression. All depression scales were highly correlated but UPDRS depression item had the lowest diagnostic value. The GDS15 had the more appropriate "receiver operating characteristics" curve. The best cut-off scores for screening depression were 17/18 for BDI and 8/9 for GDS15. We did not find any correlation between the level of depression and intensity of motor symptoms, functional capacity and duration of the disease. CONCLUSION: GDS15 is better than the BDI and the UPDRS for screening depression in PD and depression is not related to the degree of parkinsonian symptoms.