Systematic Review of Psychiatric Observation Units and Their Impact on Emergency Department Boarding

Alastair W. Magarey, Jianfeng Weng, Jeffrey C.L. Looi, Stephen Allison, Tarun Bastiampillai

Research output: Contribution to journalReview articlepeer-review

1 Citation (Scopus)


Objective: To investigate the effectiveness of acute short-stay hospital admissions in psychiatric observation units for improving the flow of patients with mental health presentations through the emergency department (ED). 

Data Sources: CINAHL, MEDLINE, OVID, PsycINFO, PubMed PubMed, Web of Science, and Google Scholar were systematically searched for English-language studies from 1990 onward. Descriptors used to describe psychiatric observation units were identified, and in databases with MESH term availability, the terms “mental disorder” and “emergency services, psychiatric” were also utilized to further enhance the search. 

Study Selection: A total of 6,571 studies were screened. The PICOS framework was used to determine the inclusion and exclusion criteria, and the process of study selection followed PRISMA guidelines. Articles were included if the unit studied had a length of stay (LOS) < 72 hours and if patients suffered from a mental health condition and were treated as hospital inpatients. 

Data Extraction: Reviewers performed data extraction and quality assessment of the included studies following the review protocol. 

Results: A total of 14 psychiatric observation unit studies were included in the review: 5 in North America and 9 in Australia. Most of these units were in large urban general hospitals. There appears to be some improvement in ED LOS for patients with mainly crisis mental health presentations. Seven of the 14 studies specifically discussed ED LOS, and 6 of these studies showed mild to moderate improvement in ED LOS, ranging from 17 minutes to > 11 hours. 

Conclusions: Psychiatric observation units were mainly located in North American and Australian settings. These units may reduce ED LOS based on limited, poor-quality evidence. Further research is required to determine whether psychiatric observation units have ongoing effects on ED LOS and alleviate access block.

Original languageEnglish
Article number22r03468
Number of pages11
JournalPrimary Care Companion for CNS Disorders
Issue number6
Publication statusPublished - 7 Nov 2023


  • short-stay hospital admissions
  • psychiatric observation units
  • mental health care
  • patient flow


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