The prevalence of mental disorders among homeless people in high-income countries: An updated systematic review and meta-regression analysis

Abstract

Background Homelessness continues to be a pressing public health concern in many countries, and mental disorders in homeless persons contribute to their high rates of morbidity and mortality. Many primary studies have estimated prevalence rates for mental disorders in homeless individuals. We conducted a systematic review and meta-analysis of studies on the prevalence of any mental disorder and major psychiatric diagnoses in clearly defined homeless populations in any high-income country. Methods and findings We systematically searched for observational studies that estimated prevalence rates of mental disorders in samples of homeless individuals, using Medline, Embase, PsycInfo, and Google Scholar. We updated a previous systematic review and meta-analysis conducted in 2007, and searched until 1 April 2021. Studies were included if they sampled exclusively homeless persons, diagnosed mental disorders by standardized criteria using validated methods, provided point or up to 12-month prevalence rates, and were conducted in high-income countries. We identified 39 publications with a total of 8,049 participants. Study quality was assessed using the JBI critical appraisal tool for prevalence studies and a risk of bias tool. Random effects meta-analyses of prevalence rates were conducted, and heterogeneity was assessed by meta-regression analyses. The mean prevalence of any current mental disorder was estimated at 76.2% (95% CI 64.0% to 86.6%). The most common diagnostic categories were alcohol use disorders, at 36.7% (95% CI 27.7% to 46.2%), and drug use disorders, at 21.7% (95% CI 13.1% to 31.7%), followed by schizophrenia spectrum disorders (12.4% [95% CI 9.5% to 15.7%]) and major depression (12.6% [95% CI 8.0% to 18.2%]). We found substantial heterogeneity in prevalence rates between studies, which was partially explained by sampling method, study location, and the sex distribution of participants. Limitations included lack of information on certain subpopulations (e.g., women and immigrants) and unmet healthcare needs. Conclusions Public health and policy interventions to improve the health of homeless persons should consider the pattern and extent of psychiatric morbidity. Our findings suggest that the burden of psychiatric morbidity in homeless persons is substantial, and should lead to regular reviews of how healthcare services assess, treat, and follow up homeless people. The high burden of substance use disorders and schizophrenia spectrum disorders need particular attention in service development. This systematic review and meta-analysis have been registered with PROSPERO (CRD42018085216). Trial registration PROSPERO CRD42018085216.

Homelessness among psychiatric inpatients in North Rhine-Westphalia: a retrospective routine data analysis

“…Homelessness is considered an increasing social problem in developed countries [ 20 ] . The overall mortality and morbidity, including mental health problems, are clearly higher among homeless persons than amongst the general population [ 2 , 18 ]. Mental disorders are also among the risk factors for age-standardized excess mortality rates in this group [ 29 ], which are 2–5 times higher than in the general population.…”

“…Mental disorders are also among the risk factors for age-standardized excess mortality rates in this group [ 29 ], which are 2–5 times higher than in the general population. Since the burden of psychiatric morbidity in homeless persons is substantial and there are strong indications of a complex relationship between homelessness and mental disorders as they promote each other and lead to poor healthcare outcomes [ 3 , 18 ].…”

Differences in Clinical Outcomes of Adults Referred to a Homeless Transitional Care Program Based on Multimorbid Health Profiles: A Latent Class Analysis

“…We retrieved demographic data (i.e., sex, age, race, referral source, insurance), medical diagnoses (e.g., cardiovascular, chronic pulmonary, other end organ disease, diabetes), substance use diagnoses (e.g., alcohol use disorder, opioid use disorder, stimulant use disorder), and mental illness diagnoses (e.g., psychotic disorder, mood disorder, anxiety/trauma related disorders) according to ICD, Tenth Revision (ICD-10) codes ( 19 – 21 ) (see Supplementary 1 ). We chose these 10 diagnoses (risk factors) based on the high prevalence of such disorders amongst PEH ( 22 , 23 ) and consensus of three individuals with expertise in providing medical and psychiatric care for PEH. We obtained encounter information (i.e., admissions, length of stay, ED visits, and outpatient visits within 12 months after program referral) and clinical outcomes (i.e., mortality and drug overdose at 12 months after program referral).…”

Drug Overdoses During the COVID‐19 Pandemic Among Recently Homeless Individuals

“…The outsized direct impact of the pandemic on the homeless population and their pre‐existing risk factors present concerns about disproportionate indirect impacts, particularly in relation to substance‐related outcomes. Drug overdose is a leading cause of morbidity and mortality in the homeless population and baseline rates of substance use disorders are several‐fold higher among individuals experiencing homelessness compared to their housed counterparts [ 19 , 20 , 21 ]. Individuals experiencing homelessness stand to benefit greatly from substance use treatments and harm reduction services [ 22 ].…”