Purpose This study aims to review international literature systematically to estimate the prevalence of homelessness among incarcerated persons at the time of imprisonment and the time of discharge. Design/methodology/approach A systematic review methodology was used to identify quantitative observational studies that looked at the prevalence of homelessness at the time of imprisonment, or up to 30 days prior to that point (initial homelessness), and at the time of discharge from prisons. Studies reported in English from inception to 11 September 2019 were searched for using eight databases (PsycInfo, Medline, Embase, CINAHL, PsycArticles, Scopus, Web of Science and the Campbell Collaboration), in addition to grey literature. Studies were screened independently by three researchers. Results of studies meeting inclusion criteria were meta-analysed using a random effects model to generate pooled prevalence data. Findings A total of 18 out of 2,131 studies met the inclusion criteria. All studies originated from the USA, Canada, UK, Ireland or Australia. The estimated prevalence of initial homelessness was 23.41% and at time of discharge was 29.94%. Substantial heterogeneity was observed among studies. Originality/value People in prisons are over twenty times more likely to be homeless than those in the general population. This is likely attributable to a range of health and social factors. Studies in this analysis suggest higher rates of homelessness in minority populations and among those with mental illnesses and neurodevelopmental disorders. While there was significant heterogeneity among studies, the results highlight the global burden of this issue and a clear necessity for targeted interventions to address homelessness in this population.

Background: This cross-sectional study sought to establish the prevalence of homelessness amongst inpatients in two psychiatric units in Ireland, and explore the perceived relationship between psychiatric illness and homelessness.Methods: The study employed a semistructured interview format utilising a specifically designed questionnaire which received ethical approval from the Limerick University Hospitals Group ethics committee. Results: Fifty psychiatric inpatients were interviewed. Fifteen were either "currently" homeless (n=8) or had experienced "past" homelessness (n=7). Those who had experienced homelessness were more likely to have a psychotic illness. A majority of those who had experienced homelessness believed that psychiatric illness contributed to their homelessness. involuntary admission rates were more than double for patients in the homeless group. A number of participants also reported that a lack of accommodation was preventing their discharge. Conclusion: Homelessness affects a significant number of psychiatric patients and can be both a contributory factor to, and consequence of, mental illness. With homelessness at unprecedented levels, there is a need for the development of tailored programmes aimed at supporting these vulnerable groups.