Early Detection of Depression in Parkinson's Disease: Psychometrics and Diagnostics of the Spanish Version of the Beck Depression Inventory

Objective: Depression is one of the most disabling non-motor symptoms in Parkinson's disease (PD) and requires proper diagnosis as it negatively impacts patients' and their relatives quality of life. The present study aimed to examine the psychometric and diagnostic properties of the Beck Depression Inventory-I (BDI-I) in a Spanish PD cohort. Method: Consecutive PD outpatients completed the Spanish version of the BDI-I and other questionnaires assessing anxiety and apathy. Patients' caregivers completed the depression/dysphoria domain of the Neuropsychiatric Inventory (NPI-D). The internal consistency, convergent and divergent validity and the factorial structure of BDI-I were evaluated, and an optimal cut-off was defined by means of the Youden index. Results: The BDI-I proved to have a good internal consistency and was underpinned by a mono-component structure. Regarding construct validity, the BDI-I was substantially related to anxiety and apathy measures in PD. Furthermore, the BDI-I overall showed good accuracy with adequate sensitivity and specificity. The optimal cut-off point was defined at 10. Conclusions: We provided evidence of the psychometric and diagnostic properties of the Spanish version of the BDI-I as a screening tool for depression in Spanish speaking PD patients, suggesting its usefulness in clinical research and practice.