Novel pharmaceuticals in the treatment of psychosis in Parkinson’s disease

Abstract

Parkinson’s disease (PD) affects 10 million people worldwide. Half will develop psychosis, the majority experiencing hallucinations rather than delusions. Emergence of psychosis increases the likelihood of institutionalization and mortality. Where pharmacological treatment is warranted, options are limited. Most currently licensed atypical antipsychotics are ineffective or worsen motor symptoms in people with PD. This review of provides an overview of the current landscape of treatments and the opportunities in emerging research. Clozapine is the only licensed antipsychotic with proven efficacy, although the associated side effects limit its use. With recent advances in understanding the role of serotonin, rational drug design approaches have delivered a novel pharmacological treatment with recently proven efficacy in clinical trials of people with PD and psychosis. Pimavanserin represents an important addition to treatment.

Keywords::

• hallucinations
• Parkinson’s disease
• psychosis
• treatment
• trials

Acknowledgement

This article presents independent research partially-supported by the National Institute for Health Research (NIHR). The views expressed are those of the author(s) and not necessarily those of the NHS, the NIHR or the Department of Health. MB is funded by the Edmond and Lily Safra Foundation.

Financial & competing interests disclosure

C Ballard, A Corbett and M Broadstock would like to acknowledge the support of the National Institute for Health Research (NIHR) Mental Health Biomedical Research Centre and Dementia Unit at South London and Maudsley NHS Foundation Trust and Institute of Psychiatry, King’s College London. C Ballard has received grants and honoraria from Lundbeck, Novartis, Bial, Acadia, Otsuka, Roche and Orion pharmaceutical companies. A Corbett has received speaking and consultancy honoraria from Acadia, Bial, Novartis and Lundbeck pharmaceutical companies. M Broadstock is funded by the Edmond and Lily Safra Foundation. The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.

No writing assistance was utilized in the production of this manuscript.

Key issues

• Psychosis commonly affects people with Parkinson’s disease, yet there are few treatment options available

• Pimavanserin has recently shown efficacy in treating psychosis in people with Parkinson’s disease and is currently under consideration for FDA approval.

• Clozapine is the only other antipsychotic shown to have efficacy in RCTs, but toxicity associated with use limits its usefulness

• Non-pharmacological approaches may be helpful in addressing distress, but there is no evidence that they impact on psychosis