Treating psychosis in movement disorder patients: a review

Psychosis is a major psychiatric problem that often occurs at the interface of psychiatry and the neurological specialty of movement disorders. Psychotic syndromes are common in treated movement disorder patients, and almost all antipsychotic drugs produce movement disorders. There is little published data on psychosis in movement disorders aside from Parkinson's disease (PD).

In this review, we focus primarily on PD, in which about 30% of treated patients have visual hallucinations and 5-10% have paranoid delusions; dementia with Lewy bodies, a variant of PD in which dementia occurs early and psychotic symptoms are common; Huntington's disease (HD), an inherited disorder that causes behavioral problems, frequently including psychosis; and tardive dyskinesia (TD), a group of movement disorder syndromes caused by antipsychotic drugs. All articles were reviewed in each of the more common movement disorders and indexed in PubMed with keywords including psychosis, psychotic symptoms, antipsychotics, hallucinations and delusions.

Although there are no approved drugs for treating psychotic symptoms in any of the movement disorders, pimavanserin, a 5-HT2A inverse agonist, is thought likely to gain approval in 2015 for treating PD psychosis. We present evidence that clozapine is currently the drug of choice for treating psychosis in patients with parkinsonism; however, blood monitoring requirements make it difficult to use. The choice of treatment of hyperkinetic disorders such as HD and the TD disorders depends on the clinical scenario.