Mood disorders in Parkinson's disease.

An increasing emphasis has been placed on the identification and management of non-motor features of Parkinson's disease (PD). Of the behavioural disorders in PD, mood disorders are amongst the most common and can occur in both early and late stages of PD. In some cases, these problems may even precede the development of motor symptoms of PD. These disorders have a major impact in the quality of life and affect daily function. This review will focus on depression, anxiety and apathy, and will discuss the epidemiological, clinical features, diagnosis and management of these disorders. The diagnosis and evaluation of these problems remain a challenge in view of the overlapping symptoms between these disorders and also with the clinical features of PD. The development and validation of diagnostic criteria and rating scales for these disorders remain a priority particularly in relation to anxiety and apathy. Another gap in the management of these disorders is the limited empirical evidence for the treatment of these problems. There is therefore an urgent need for systematic studies in the pharmacological and non-pharmacological management of these disorders to enable a holistic and evidence-based approach to the management of mood disorders in PD.