The term dual diagnosis is a common, broad term that indicates the simultaneous presence of two independent medical disorders. Recently, within the fields of mental health, psychiatry, and addiction medicine, the term has been popularly used to describe the coexistence of a mental health disorder and AOD problems. The equivalent phrase dual disorders also denotes the coexistence of two independent (but invariably interactive) disorders, and is the preferred term used in this Treatment Improvement Protocol (TIP).
Common examples of dual disorders include the combinations of major depression with cocaine addiction, alcohol addiction with panic disorder, alcoholism and polydrug addiction with schizophrenia, and borderline personality disorder with episodic polydrug abuse. Although the focus of this volume is on dual disorders, some patients have more than two disorders, such as cocaine addiction, personality disorder, and AIDS. The principles that apply to dual disorders generally apply also to multiple disorders.
The combinations of AOD problems and psychiatric disorders vary along important dimensions, such as severity, chronicity, disability, and degree of impairment in functioning. For example, the two disorders may each be severe or mild, or one may be more severe than the other. Indeed, the severity of both disorders may change over time. Levels of disability and impairment in functioning may also vary.