Unmet needs in the diagnosis and treatment of Parkinson's disease psychosis and dementia-related psychosis.

Dementia due to Parkinson's disease and Alzheimer's disease are associated with behavioural and psychological symptoms, including psychosis. Long-term management presents a challenge for health care providers and caregivers. Symptoms of psychosis include hallucinations and delusions; if untreated, these can lead to institutionalisation, decreased quality of life, and significant patient and caregiver distress. A critical step in the effective management of dementia-related psychosis (DRP) is the identification and diagnosis of affected patients. The lack of a standardised diagnostic approach presents a barrier to treatment and there are no consensus guidelines for DRP. Furthermore, there are no approved therapies for the treatment of DRP. Antipsychotic medications are often prescribed off-label, even though some are associated with an increased risk of adverse events or mortality. We present currently available screening tools and guidelines for the diagnosis and treatment of Parkinson's disease psychosis and DRP in the context of what is needed for effective management of psychosis.KEY POINTSWe present currently available screening tools and guidelines for Parkinson's disease psychosis and dementia-related psychosis, and discuss the unmet need for simple clinical diagnostic tools and treatment guidelines.The identification of psychosis is variable across different settings and specialties, without a unified approach to screening, definition, or diagnosis.Currently used tools for defining and assessing psychosis in a research setting are usually too cumbersome for everyday clinical practice.The development of a standardised set of diagnostic criteria would provide clinicians the opportunity to improve the detection, treatment, and quality of life of patients and their caregivers.