An increasing number of children, adolescents and adults with intellectual disabilities and/or autism are being admitted to general psychiatric wards and cared for by general psychiatrists.

The aim of this systematic review was to consider the likely effectiveness of in-patient treatment for this population, and compare and contrast differing models of in-patient care.

A systematic search was completed to identify papers where authors had reported data about the effectiveness of in-patient admissions with reference to one of three domains: treatment effect (e.g. length of stay, clinical outcome, readmission), patient safety (e.g. restrictive practices) and patient experience (e.g. patient or family satisfaction). Where possible, outcomes associated with admission were considered further within the context of differing models of in-patient care (e.g. specialist in-patient services versus general mental health in-patient services).

A total of 106 studies were included and there was evidence that improvements in mental health, social functioning, behaviour and forensic risk were associated with in-patient admission. There were two main models of in-patient psychiatric care described within the literature: admission to a specialist intellectual disability or general mental health in-patient service. Patients admitted to specialist intellectual disability in-patient services had greater complexity, but there were additional benefits, including fewer out-of-area discharges and lower seclusion rates.

There was evidence that admission to in-patient services was associated with improvements in mental health for this population. There was some evidence indicating better outcomes for those admitted to specialist services.

The Mental Health Act in England and Wales allows for two types of detention in hospital: civil and forensic detentions. An association between the closure of mental illness beds and a rise in civil detentions has been reported.

To examine changes in the rate of court orders and transfer from prison to hospital for treatment, and explore associations with civil involuntary detentions, psychiatric bed numbers and the prison population.

Secondary analysis of routinely collected data with lagged time series analysis. We focused on two main types of forensic detentions in National Health Service (NHS) hospitals and private units: prison transfers and court treatment orders in England from 1984 to 2016. NHS bed numbers only were available.

There was an association between the number of psychiatric beds and the number of prison transfers. This was strongest at a time lag of 2 years with the change in psychiatric beds occurring first. There was an association between the rate of civil detentions and the rate of court orders. This was strongest at a time lag of 3 years. Linear regression indicated that 135 fewer psychiatric beds were associated with one additional transfer from prison to hospital; and as the rate of civil detentions increased by 72, the rate of court treatment orders fell by one.

The closure of psychiatric beds was associated with an increase in transfers from prison to hospital for treatment. The increase in civil detentions was associated with a reduction in the rate of courts detaining to hospital individuals who had offended.

None.