Clinical research and practice have established that IOT is an effective and viable way for individuals with a range of substance use disorders to begin their recovery. In the 1980s, it commonly was believed that only clients who were relatively high functioning, employed, and free of significant co-occurring psychiatric disorders could benefit from IOT and that IOT was not effective with clients who were compromised by significant psychosocial stressors such as homelessness or co-occurring disorders. Today substantial research and clinical experience indicate that IOT can be effective for clients with a range of biopsychosocial problems, particularly when appropriate psychiatric, medical, case management, housing, and other support services are provided.