Trường hợp có bằng chứng cho thấy comorbidity, lạm dụng thuốc và rối loạn hành vi dường như là tiền đề cho cả hai vô gia cư và những cơn loạn tâm thần ở hầu hết các trường hợp. Đối với các tác giả, những phát hiện này cho thấy một giới hạn trong phạm vi các dịch vụ tâm thần | THE HOMELESS MENTALLY ILL 233 maintained contact with psychiatric services. Where there was evidence of comorbidity substance abuse and behavioural disturbance appeared to be antecedent to both homelessness and the onset of psychosis in most cases. For the authors these findings suggest a limit to the extent to which psychiatric services may be able to prevent homelessness among people with severe mental illness. Substance abuse and the absence of family support are key factors contributing to homelessness among people with psychotic disorders. This suggests that further services for people with comorbid psychotic and substance abuse disorders including residential provision are required. Additional interventions should also target patients with adverse childhood experiences and poor ongoing support. While not discounting the mental health care needs of homeless people with psychotic disorders this aspect has arguably been overemphasized while the similarities between homeless people who are mentally ill and their non-mentally-ill counterparts deserve greater attention 41 An integrated approach in which mental health services complement and support other agencies tackling homelessness is necessary. PATHWAYS TO HOMELESSNESS FOR THE MENTALLY ILL Sullivan el al. 14 explored pathways to homelessness for mentally ill persons by examining mental illness as a risk factor for homelessness as distinct from other personal vulnerabilities such as histories of poverty abuse or family instability that are likely to increase the risk of homelessness when affordable housing is in short supply. Since a longitudinal study of a community sample over many years with repeated assessments of all potential risk factors including mental illness would be prohibitively expensive they used data from two existing data sets the COH project described in Sullivan el al. 14 and the National Epidemiological Catchment Area ECA Survey 29 . To examine pathways to homelessness they conducted three .
