Cognitive and psychiatric aspects of Parkinson's disease: Treatment recommendations

Parkinson's disease, a progressive disorder which leads to significant functional disability, is the second most common neurodegenerative disorder in the elderly. In the majority of individuals, the illness is complicated by co-occurring psychiatric problems. These disorders may complicate the course and management of the illness and lead to poor outcomes. Psychiatric disorders are under-recognized in clinical practice for a variety of reasons, and there is relatively little controlled research that can guide treatment. The etiology of these disorders is not well understood but some, including psychosis and disinhibition (which leads to gambling and hypersexuality), can be as a direct result of the dopaminergic medications used in the treatment of the movement disorder. This article reviews treatment recommendations, based on available evidence and clinical experience, for the most common of the psychiatric disorders, including depression, psychosis, disinhibition, cognitive impairment, sleep disorders and anxiety. Much research is needed to more definitively define these disorders and their treatment.