“…The 29 included studies encompass samples of adults experiencing homelessness in three countries: 16 (55%) studies in the USA, 12 (41%) studies in Canada, and one (3%) study in the UK. The main recruitment sites were homeless shelters (18 studies),[29][30][31][32]35,36,[39][40][41][42][44][45][46][47]51,52,56,57 clinics and facilities that provide services to people experiencing homelessness (20 studies),29,30,33,34,36,37,39,40,42-45,48, 49,51-54,56,57 and street or outdoor encampments (14 studies). 29-32,36,40,41,44,46,47,51,55-57 Included studies recruited homeless young adults (ten [34%] studies), homeless adults (nine [31%] studies), homeless adults with mental illness (five [17%] studies), older homeless adults (one [3%] study), homeless mothers (one [3%] study), homeless adults with a dual diagnosis of mental illness and substance use disorder (one [3%] study), homeless young adults with psychosis (one [3%] study), and homeless young adults involved in commercial sex (one [3%] study).…”