Among our sample of homeless adults with mental illness, we found a significant relationship between a history of childhood foster care placement and a number of indicators of socio-demographic risk, poor mental and physical health, and problematic substance use in adulthood. Foster care history independently predicted incomplete high school, duration of homelessness, discontinuous work history, meeting criteria for a current mental disorder in the less severe cluster, multiple mental disorders, early initiation of alcohol and/or drug use, and daily drug use. Our study is the first to examine a range of different adult substance use outcomes (i.e., type, frequency, poly-substance use, age of initiation) among homeless adults with mental illness and histories of foster care placement.
Foster care placement independently predicted substance use problems in our adult sample, specifically early initiation (before age 14) of drug and/or alcohol use and daily drug use. Abuse of alcohol and other drugs places adolescents at greater risk of homelessness, although it may not be a direct causal factor [27]. Compared to their non-homeless counterparts, homeless youth use substances earlier and with greater frequency [28,29]. Further, Thompson and Hasin [30] reported that homeless youth with histories of foster care were almost nine times more likely to have been in drug treatment than homeless youth without such histories, even after adjusting for demographics, other adverse childhood events, prior arrest, unemployment and educational attainment.
Our findings suggest that daily drug use may be a common mediator for a range of early risk factors [31]. Previous research using our sample of homeless adults with mental disorders found that daily drug use was independently predicted by self-report of childhood learning disabilities [32] and adverse childhood experiences [33]. In the latter study, we found a strong relationship between the breadth of exposure to abuse or household dysfunction during childhood (i.e., the number of adverse childhood events) and a number of indicators of poor mental and physical health as well as problematic substance use in adulthood (e.g., daily drug use). In turn, previous work with the same sample has shown that daily drug use significantly predicts the duration of adult homelessness [34] and the severity of mental health symptoms [35].
The current study did not examine other potential mediators such as self-esteem or shame; however, one could assume that strong manifestations of these psychological states might manifest in the mental disorders examined in our study. Daily drug use and other potential mediators (e.g., emotion regulation skills, access to social support and early intervention, antisocial behaviors) need to be examined in future studies using path-type analysis. Cross-sectional, retrospective data cannot disentangle the unique predictors of homelessness and mental illness, but it is likely that adverse childhood experiences, particularly foster care placement, have both direct and indirect (perhaps mediated by substance use) effects on a range of adult health and social outcomes. Thus, among homeless adults with mental disorders, a history of early and persistent substance abuse may be a key indicator of risk. Our findings support the need for more accessible and integrated care for homeless adults with concurrent disorders.
In addition to substance use problems, a history of foster care independently predicted meeting criteria for a less severe type of mental disorder (i.e., major depressive episode, panic disorder, PTSD) and more than one mental disorder. It makes sense that foster care placement would contribute to mood and anxiety disorders more so than psychosis. However, Roos et al. [19] found that a history of foster care predicted adult psychotic disorders as well as depression and multiple mental disorders. While the disorders comprising our less severe cluster may appear less serious than those in the severe cluster, the disorders in the former cluster can be very debilitating. The fact that foster care predicts meeting criteria for multiple mental disorders suggests that poor psychiatric outcomes in adulthood are related to foster care, and further strengthens the case for integrated treatment for concurrent disorders for this population.
Given that over 1,000 youth exit foster care without a family each year in Canada, services and supports need to be in place to help youth address concurrent psychiatric and substance use problems prior to and after discharge. Organizations that provide services to homeless youth should target those with histories of adverse childhood events, particularly foster care, and tailor services to their collective and individual needs. Approaches such as brief motivational interviewing have been shown to reduce substance use among homeless youth in a variety of settings [36,37] and should be made more widely available as part of integrated treatment for concurrent disorders.
The significant association between foster care history and the duration of homelessness in adulthood is also of concern. Both researchers and advocates have called for more evidence-based interventions to reduce homelessness among youth exiting foster care [8,11]. Preliminary research on transitional living programs for youth exiting foster care is associated with reduced rates of street homelessness and increased employment, particularly when paired with vocational skills training [38].
In previous work, we have emphasized the importance of viewing homelessness in the context of cumulative adversity [39] and Problem Behavior Theory [40,41]. These models conceptualize homelessness as the result of successive environmental disruptions, each of which places individuals at greater risk for homelessness and associated risk factors. In addition to the effects of progressive risk, risk may be multiplied at each stage of development because the environmental risks associated with later phases present increasingly greater challenges to development and adaptation. Problem Behavior Theory hypothesizes that various early risk factors may comprise a cluster of risky behaviors that mediate the link from childhood adversity to a variety of adverse adult outcomes, rather than distinct independent pathways. Our findings, alongside others’, suggest that the relationship between foster care placement and adult homelessness (and the associated health and social problems we identified) may be mediated by problem behaviours such as heavy substance use. Further, it is likely that the number of adverse events (e.g., adverse childhood events in addition to foster care, incomplete high school, early problems with substance use and/or the law, lack of institutional or family support) may be more important in predicting negative adult health and social outcomes than any one event. Daily or heavy substance use must be tested as a mediating factor alongside other potential mediators.
Placement in out-of-home care is a significant and salient event that should indicate appropriate interventions for both children and parents. Early interventions in childhood might change or moderate the cycle of homelessness across generations because early risk factors are often longstanding and drive a trajectory of cumulative risk, potentially leading to severe psychopathology and social exclusion. Among our sample of homeless adults, 31% had children currently or previously in foster care, suggesting that foster care placement is a form of trauma that has inter-generational effects.
Limitations
Despite the strengths of our study design (i.e., large sample size, structured diagnostic interviews), several limitations must be considered. First, all variables were based on participant self-report. Given that participants were selected based on presence of a current mental disorder, accuracy of recall may have been compromised. Further, the baseline interview occurred before randomization to a housing intervention and therefore may have led some participants to modify their responses. It is unlikely that participants purposefully modified their responses to the foster care items given that they were administered after the baseline interview. Furthermore, foster care is a highly salient event that is likely to be remembered; however, recall error could have occurred in questions pertaining to the reason for being placed in care.
Additionally, data were not available to examine whether participants’ biological mothers had abused substances during pregnancy, the age participants first entered foster care, the total length of time they spent in foster care, and number and types of residential and educational placements. As each of these factors has been shown to increase the risk for subsequent psychiatric disorders, the effect of these factors on the risk for psychiatric and substance use disorders should be examined in future research. In addition to the above noted variables, we did not have access to several other important variables necessary for conducting a robust path analysis in order to more fully investigate the links between foster care placement and adverse outcomes among homeless adults (e.g., early problem behaviors, social support, affect regulation skills, self-esteem/self-concept, and the availability of treatment/institutional supports). Future longitudinal studies should examine foster care in the context of other adverse childhood events, early problem behaviors that have been identified in the literature (e.g., adolescent substance use, involvement with the law, incomplete high school), as well as key adult outcomes, in order to investigate the key pathways that link foster care to adverse outcomes among homeless adults with mental illness.