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

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). CINAHL, MEDLINE, OVID, PsycINFO, 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.