Authors' objectives: People experiencing mental health crises in the community often present to emergency departments and are admitted to a psychiatric hospital. Because of the demands on emergency department and inpatient care, psychiatric decision units have emerged to provide a more suitable environment for assessment and signposting to appropriate care. The study aimed to ascertain the structure and activities of psychiatric decision units in England and to provide an evidence base for their effectiveness, costs and benefits, and optimal configuration. Mental health crisis care is under intense pressure in the UK and in equivalent systems internationally. Mental health attendances at emergency departments (EDs) are increasing while the number of available psychiatric inpatient beds is decreasing, resulting in challenges to the ED system and lengthy waits for people in mental health crisis. Poor experiences and low levels of satisfaction with mental health care all point to the ED as being a far from ideal environment for support and treatment for mental health crisis. People experiencing mental health crises are often admitted to an acute psychiatric ward. Psychiatric inpatient stays can be costly, in some cases detrimental to mental health, disproportionately harmful to people from some minority ethnic groups and reportedly unnecessary for as many as 17% of referred individuals. To address these growing challenges, policy in England has called for the development and evaluation of new, more effective, models of crisis care. Alongside street triage, crisis houses and crisis cafes, psychiatric decision units (PDUs) have emerged as one of a number of responses. There is no single service specification for PDUs in England but rather a shared set of characteristics. PDUs are short-stay facilities, based either at psychiatric or general hospital sites, offering time-limited care (typically up to 24–72 hours) including overnight stay. The focus of PDUs is on providing a comprehensive assessment in a calm, safe environment, offering therapeutic input as appropriate, and onward signposting and referral to a range of community-based care, both within and outside the NHS. Staff-to-patient ratio – at around one to two – can be higher than an inpatient ward (typically around one to four). PDUs are often nurse led, supported by healthcare assistants, with consulting input from psychiatry. Overnight accommodation generally comprises reclining seating rather than beds. Units tend to be small, with a capacity of around six to eight. The aim of the study was to ascertain the structure and activities of operational PDUs in England and to provide an evidence base for their effectiveness, costs and benefits, and optimal configuration. The study addressed the following research questions: What is the range of hospital-based, short-stay interventions internationally designed to reduce admissions to acute psychiatric inpatient care and what is their effectiveness? What is the scope and prevalence of PDUs nationally and how are they configured? How has the introduction of PDUs impacted on psychiatric inpatient admissions and ED psychiatric episodes/breaches? What are the care pathways before and following an admission to the PDU? What is the impact of the introduction of PDUs on inequalities of access to acute mental health services? How do service users experience PDUs and crisis care pathways before and after admission to PDU? How are decisions made about referral and admission to PDU, and assessment and onward signposting and referral? How do the economic costs and impacts of PDUs compare with areas without PDUs? How do the costs for individual service users following PDU implementation compare with their costs prior to the introduction of PDUs to crisis care pathways?

Authors' results and conclusions: Psychiatric decision units have the potential to reduce informal psychiatric admissions, mental health presentations and wait times at emergency department. Cost savings are largely marginal and do not offset the cost of units. First-time referrals to psychiatric decision units use more inpatient and community care and less emergency department-based liaison psychiatry in the months following the first visit. Psychiatric decision units work best when configured to reduce either informal psychiatric admissions (longer length of stay, higher staff-to-patient ratio, use of psychosocial interventions), resulting in improved quality of crisis care or demand on the emergency department (higher capacity, shorter length of stay). To function well, psychiatric decision units should be integrated into the crisis care pathway alongside a range of community-based support. Our mapping exercise revealed PDUs in just six MHTs in England, of various configurations, with a small number of other units recently decommissioned and more about to open. The ITS study demonstrated a reduction in informal psychiatric admissions post PDU opening in some sites and overall, but with no clear continuing trend in admissions. Formal admissions increased overall and there was no change in overall levels of inpatient psychiatric activity following the opening of a PDU. There was reduction in ED-based liaison psychiatric episodes in one site but an upward trend continued overall. Mental health presentations at ED dropped in the same site but with, again, no overall change. There was no change in breaches of 4-hour waits in EDs and overall length of wait increased. The implementation of other crisis services (e.g. street triage) in the study period were shown to consolidate the effect of PDUs. In the synthetic control study, there was no overall change in rate of total psychiatric admissions in study sites compared with controls post PDUs opening, but length of psychiatric inpatient stays was shorter in some sites and overall. Rate of mental health presentations at the ED was lower than controls at one site but not overall, while length of ED waits and proportion of waits breaching 4-hour targets were again lower at one site compared with control but unchanged overall. The cohort study indicated that use of both inpatient and community mental health care was significantly higher post visit to PDU than pre first visit at all sites (while numbers of ED-based liaison psychiatry episodes dropped at some sites). There were few differences in service use between pre-pandemic and primary cohorts, although community mental health service contacts were more likely to be remote and less likely to be face to face, and contacts with crisis resolution and home treatment teams reduced in some sites during the pandemic. First-time visitors to PDU were more likely to be younger than trust-wide populations, and at some sites more likely to be male and less likely to be White British. In the qualitative interview study, many people staying on PDUs found them safe, calming and supportive and appreciated the opportunity to talk in depth to staff members. However, in some cases they reported being discharged too quickly while still feeling suicidal, and they indicated that PDUs were only as effective as the support in the community that they were signposted to. PDU staff found work on the units rewarding, including the additional responsibility that came with working on nurse-led units, and felt supported in the team, but work was emotionally demanding and could result in high staff turnover. Staff referring to PDUs felt units were valuable but sometimes had different expectations of the function of PDUs and tension could arise between PDU and referring teams where communication was not as clear as it might be. The economic analysis estimated that there were marginal savings (and some increases in cost) relating to within-site changes in psychiatric inpatient and ED attendance activity, and larger savings compared with controls resulting from overall shorter psychiatric admissions (mostly driven by findings at one site) and lower rates of ED attendances at some sites. The costs of operating PDUs varied in relation to staff-patient ratios, as did per visit costs, which were also impacted by average length of stay on units. These costs substantially outweighed any savings from PDUs (except at our outlier site where length of psychiatric stay was reduced compared with control in one analysis). There were additional individual-level costs associated with increased inpatient and community mental health service use following the first visit to a PDU. However, this was a short-term view that did not take into account potential gains to quality of life indicated by our data (neither did we assess possible non-NHS cost savings). Modelling indicated the PDUs may be cost-effective in certain scenarios and that this warrants further research. Our synthesis indicated that, where staff–patient ratio was higher and length of stay longer, PDUs have the potential to reduce informal psychiatric admissions and improve quality of care for a group of people who have high levels of acute needs but who might not benefit from inpatient admission (these units cost more to operate). PDUs with higher capacity and shorter length of stay might impact mental health attendances in the ED (this distinction reflects findings internationally in our systematic review). In either case, PDUs should not be commissioned with the expectation of a simple financial return on investment. However, where PDUs are configured with a clear aim in mind and integrated alongside a range of crisis and community mental health support, they improve quality of care and facilitate access to appropriate care, potentially reducing level and cost of acute and emergency mental health service use.

Authors' methods: This was a mixed-methods study comprising survey, systematic review, interrupted time series, synthetic control study, cohort study, qualitative interview study and health economic evaluation, using a critical interpretive synthesis approach. The study took place in four mental health National Health Service trusts with psychiatric decision units, and six acute hospital National Health Service trusts where emergency departments referred to psychiatric decision units in each mental health trust. Participants in the cohort study (n = 2110) were first-time referrals to psychiatric decision units for two 5-month periods from 1 October 2018 and 1 October 2019, respectively. Participants in the qualitative study were first-time referrals to psychiatric decision units recruited within 1 month of discharge (n = 39), members of psychiatric decision unit clinical teams (n = 15) and clinicians referring to psychiatric decision units (n = 19). The availability and quality of data imposed limitations on the reliability of some analyses. This was a mixed-methods study in six work packages (WP): WP1 – systematic review and service mapping; WP2 – interrupted time series (ITS); WP3 – synthetic control study; WP4 – cohort study; WP5 – qualitative interview study; WP6 – health economic analysis. With the exception of WP1, the study took place in four sites; sites were mental health NHS trusts that had an operational PDU, and the EDs at NHS hospitals in the same locality as the mental health trust (MHT) that referred to the PDU. WP1: service mapping We conducted a survey of PDUs in England, establishing their prevalence and structure, and how they complement other NHS crisis care services locally. Participants were freedom of information officers and mental health service managers at all mental health NHS trusts in England (n = 53). A 29-item questionnaire was developed to determine whether mental health NHS trusts had a PDU, the operational structure of PDUs and the existence of alternative assessment and crisis care provision. Descriptive statistics were used to present survey findings.

Project Status: Completed

URL for project: https://www.journalslibrary.nihr.ac.uk/programmes/hsdr/17/49/70

Year Published: 2023

URL for published report: https://www.journalslibrary.nihr.ac.uk/hsdr/PBSM2274

URL for additional information: English

English language abstract: An English language summary is available

Publication Type: Full HTA

Country: England, United Kingdom

DOI: 10.3310/PBSM2274

Organisation Name: NIHR Health Services and Delivery Research programme

Contact Address: NIHR Journals Library, National Institute for Health and Care Research, Evaluation, Trials and Studies Coordinating Centre, Alpha House, University of Southampton Science Park, Southampton SO16 7NS, UK

Contact Name: journals.library@nihr.ac.uk

Contact Email: journals.library@nihr.ac.uk