Costs of services for homeless people with mental illness in 5 Canadian cities: a large prospective follow-up study.

Background: Limited evidence on the costs of homelessness in Canada is available. We estimated the average annual costs, in total and by cost category, that homeless people with mental illness engender from the perspective of society. We also identified individual characteristics associated with higher costs.

Methods: As part of the At Home/Chez Soi trial of Housing First for homeless people with mental illness, 990 participants were assigned to the usual-treatment (control) group in 5 Canadian cities (Vancouver, Winnipeg, Toronto, Montréal and Moncton) between October 2009 and June 2011. They were followed for up to 2 years. Questionnaires ascertained service use and income, and city-specific unit costs were estimated. We adjusted costs for site differences in sample characteristics. We used generalized linear models to identify individual-level characteristics associated with higher costs.

Results: Usable data were available for 937 participants (94.6%). Average annual costs (excluding medications) per person in Vancouver, Winnipeg, Toronto, Montréal and Moncton were $53 144 (95% confidence interval [CI] $46 297-$60 095), $45 565 (95% CI $41 039-$50 412), $58 972 (95% CI $52 237-$66 085), $56 406 (95% CI $50 654-$62 456) and $29 610 (95% CI $24 995-$34 480), respectively. Net costs ranged from $15 530 to $341 535. Distributions of costs across categories varied significantly across cities. Lower functioning and a history of psychiatric hospital stays were the most important predictors of higher costs.

Interpretation: Homeless people with mental illness generate very high costs for society. Programs are needed to reorient this spending toward more effectively preventing homelessness and toward meeting the health, housing and social service needs of homeless people.