Dissociative identity disorder and substance abuse: the forgotten relationship.

The treatment and research of dissociative disorders, particularly dissociative identity disorder (DID), are hampered by professional skepticism and diagnostic uncertainties. Almost always associated with severe and sustained childhood trauma, its chief manifestations are at least two distinct and separate identities which have an independent manner of existing in the world. It is also associated with a high degree of psychiatric comorbidity. Among the most frequent diagnoses found in patients with DID are substance use and dependence. For a variety of reasons there has been little dialogue among the disciplines that study patients with trauma and those that study and treat substance abuse. Clinicians dealing with a primarily substance-abusing population are likely to encounter but not recognize these patients. The authors present several representative cases illustrative of features of patients with DID. The epidemiology, phenomenology and presentation of DID, as well as its relation to posttraumatic stress disorder are discussed. Little systematic investigation exists on the treatment of DID in general, and substance abuse in DID in particular. The authors draw upon the existing literature, and their experience to discuss treatment strategies aimed at treating patients with both diagnoses. Ignoring either diagnosis is likely to be detrimental to patients; both disorders and their coexistence need to be addressed.