7 - The inpatient with dual diagnosis  pp. 113-129

The inpatient with dual diagnosis

By Michael I. Casher and Joshua D. Bess

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When specific diagnoses are mentioned, we are referring to diagnoses and criteria as listed in the Diagnostic and Statistical Manual of Mental Disorders, 4th edition, text revision (DSM-IV-TR) unless otherwise specified.

Why are patients with dual diagnosis disorders admitted to an inpatient psychiatric unit?

First, a clarification of vocabulary. In this volume the terms “dual diagnosis,” “substance use disorder[s],” “[name of substance] use,” and/or “[name of substance] dependence” are used. The first two, more general, terms are used more or less interchangeably, with recognition that a patient can have a substance use disorder (SUD) without having dual diagnosis – i.e., without a separate, primary psychiatric illness. The assumption is made that, unless mentioned specifically, clinical situations discussed here involve patients who do have a primary psychiatric illness in addition to a SUD. Also, although DSM-IV criteria differentiate between substance abuse and substance dependence, this volume, again unless specifically mentioned, does not make that distinction. Furthermore, the authors avoid the term “substance abuse” altogether, given recent evidence that this phrase propagates stigma against a very large sub-set of the psychiatric patient population.

Similar to syphilis several generations ago, addiction is the modern “great imitator” of psychiatric symptoms and syndromes, as well as a frequent concomitant of psychiatric illness. With psychiatric illness, dual diagnosis may be more the rule than the exception, with substance dependence tripling the odds of a psychiatric disorder, and psychiatric disorders similarly increasing the chances of a SUD.