Depression rating scales in Parkinson's disease: A critical review updating recent literature.

Depression is a prominent non-motor symptom in Parkinson's disease (PD). Assessing depression in PD remains a challenge due to the overlap of somatic symptoms between depression and PD. Other neuropsychiatric manifestations associated with PD, such as cognitive decline, also complicate assessment of depression. Therefore it is critical to investigate the validity of depression rating scales for use in PD. This will allow evaluation of observer- and self-report instruments to be administered in neurologically ill geriatric populations such as PD, and identification of appropriate scales to use in cognitively challenged PD patients. The present review includes all studies examining the validity of depression rating scales in PD. It discusses the usefulness of 13 depression rating scales in PD. The clinician-rated and widely used HAMD-17 and the self-report GDS scales are recommended for screening and measuring severity of depression in PD. The GDS-15 may be a preferred choice due to its brevity and ease of use design for older adults. Other valid and reliable instruments to use in PD include self-rated scales, such as the HADS-D, HDI, and the BDI, and the observer-report, MADRS. The CSDD displayed satisfactory validity and reliability for identification of PD patients with and without dementia. The PHQ-2, PHQ-10, SDS, CES-D, UPDRS-Depression item, IDS-SR, and IDS-C each showed some evidence of validity or reliability, however further research on the psychometric properties of these scales when used in a PD population are required.