Neuropsychiatric effects of Parkinson's disease treatment.

Advances in the treatment of Parkinson's disease have led to significant improvement in many of the disabling motor symptoms of the disease, but often at the cost of neuropsychiatric side-effects. These include psychosis, dopamine dysregulation syndrome, impulse control disorders, mood disorders and Parkinson's disease drug withdrawal syndromes. Such side-effects can be as disabling and have as much impact on activities of daily living, quality of life, relationships and caregiver burden as motor symptoms. Awareness of these potential side-effects is important both in terms of obtaining informed consent, and to aid early identification and intervention, as patients may not spontaneously report side-effects because of lack of insight, or deny them out of shame or embarrassment. The challenge of treatment can be a trade off between the emergence of such side-effects and the amelioration of parkinsonism, best mastered with an informed dialogue between clinician and patient.