This book provides a systematic and comprehensive discussion of the comorbidities that commonly occur when addictive diseases are associated with other psychological disturbances. The special aspects involved in the combined occurrence and specific treatment procedures in accordance with recent evidence-based research results are presented from the points of view of psychiatry and psychotherapy, as well as from the viewpoint of addiction therapy. It is essential to take a precise patient history, including the temporal sequence in which the various symptoms and problems appeared. This is the prerequisite for a correct diagnosis and forms the basis of treatment planning. The book offers practical solutions for the frequent problems of diagnosis and treatment of ?double diagnoses= and ways of dealing with patients who are often experienced as challenging in everyday clinical practice. This second edition has been fully updated, with two new chapters added on the important topics of diagnosis/classification and drug dependency.