This book is designed to help clinicians assess and treat children or adolescents with attention deficit/hyperactivity disorder who also present other disabilities. Major comorbidities are described in depth and empirically grounded guidelines are presented for evaluation and treatment. Part 1 provides an overview of issues in comorbidity, including problems with the diagnostic criteria, pitfalls in the study of comorbidity, and comorbidity and domains of functioning. Part 2 discusses psychiatric and behavioral assessment and provides assessment instruments that can be utilized both in establishing diagnoses and in identifying areas of behavioral impairment. Part 3 provides an overview of pharmacological and behavioral treatment approaches. In Part 4, the various comorbid diagnoses and specific treatments for them are discussed, including disruptive behavior disorders (which includes substance abuse), neurological disorders, affective disorders, anxiety disorders, mental retardation and pervasive developmental disorders, medical disorders, learning disorders, and obsessive-compulsive and tic disorders. Part 5 identifies potential areas of impairment and their specific treatments, including problems in home, classroom, and playground. Finally, the Epilogue discusses future directions in comorbidity research and treatment. (Contains approximately 700 references.) (CR)