Despite considerable evidence of high levels of co morbidity, drug and alcohol treatment agencies and mainstream psychiatric services often fail to identify and respond to concurrent psychiatric or drug and alcohol problems, respectively. The original review was conducted as a first step in providing clinicians working in mental health settings, hospitals, and general practice with information on screening and diagnostic instruments that may be used to assess previously unidentified co morbidity. This second edition of the review seeks to: update the original review of alcohol and other drug use and psychiatric screening / diagnostic instruments; recommend when these instruments should be used, by whom and how they should be interpreted; identify limitations and provide recommendations for further research; and refer the reader to pertinent Internet sites for further information and/or purchasing of assessment instruments. The current revision also includes information regarding special populations, specifically Indigenous Australians, older persons and adolescents.