The Practical Adolescent Dual Diagnostic Interview (PADDI) was developed as a structured diagnostic interview that covers indications of prevalent mental health conditions and substance use disorders. It is specifically designed for use with adolescents and not as an assessment tool for adults. The interview includes questions related to depressive and manic episodes, mixed states, psychosis, post-traumatic stress disorder (PTSD), panic attacks, anxiety and phobias, obsessive-compulsive disorder, conduct disorder, and possible paranoid and dependent personality disorders, as well as substance use disorders. To assess the ability of the PADDI interview questions to identify potential problem areas, anonymous data from 279 adolescents who were interviewed as part of routine clinical assessments in a variety of clinical programs were analyzed. These clinical programs use the PADDI as part of their standard clinical practice. Results support the reliability of the PADDI, however, additional investigation should be conducted to assess both test-retest and inter-rater reliability. In addition, a clear distinction was found to exist for most problem areas between those individuals meeting diagnostic criteria from those that do not. Lastly, the pattern of correlations of severity levels among the diagnostic categories is generally consistent with the literature on comorbidity. For example, PTSD correlated highly with depression, panic, and mania. References