This book fills a gap in the existing medical literature by providing a best-practice approach to the evaluation and acute treatment of patients presenting for emergency care with identifiable substance use and/or co-occurring psychiatric disorders. As the first interdisciplinary book to integrate psychiatric and emergency care, the text uniquely covers a myriad of serious medical conditions, acute mental status and dangerous behavioral abnormalities. The book focuses on guidelines that support emergency room physicians with little formal medical training in addiction medicine. The first section focuses on the diagnosis and management of substance-specific intoxication and withdrawal states, as well as common medical co-morbidities and disposition considerations. The book lends particular attention to the identification and stabilization of high risk medical conditions associated with each substance of abuse.