Merck Manual

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Substance-Induced Disorders


Mashal Khan

, MD, Weill Cornell Medicine

Last full review/revision Nov 2020| Content last modified Nov 2020
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  • Intoxication

  • Withdrawal

  • Substance-induced mental disorders

Substance-related disorders that involve pathologic patterns of behavior related to drug use (eg, patients continue to use a substance despite experiencing significant problems related to use of that substance) are considered substance use disorders Substance Use Disorders Substance use disorders are a type of substance-related disorder that involve a pathologic pattern of behaviors in which patients continue to use a substance despite experiencing significant... read more . The common terms "addiction," "abuse," and "dependence" are too loosely and variably defined to be useful in systematic diagnosis.

The specific manifestations and treatment of intoxication and withdrawal vary by the substance or substance class and are discussed elsewhere in THE MANUAL.


Intoxication refers to development of a reversible substance-specific syndrome of mental and behavioral changes that may involve altered perception, euphoria, cognitive impairment, impaired judgment, impaired physical and social functioning, mood lability, belligerence, or a combination. Taken to the extreme, intoxication can lead to overdose, significant morbidity, and risk of death.


Withdrawal refers to substance-specific physiologic effects, symptoms, and behavioral changes that are caused by stopping or reducing the intake of a substance. To be classified as a substance-withdrawal disorder, the withdrawal syndrome must cause the patient significant distress and/or impair functioning (eg, social, occupational). Most patients with withdrawal recognize that readministering the substance will reduce their symptoms.

Substance-induced mental disorders

To be considered substance-induced, the substance involved must be known to be capable of causing the disorder. Substances can be members of the 10 classes of drug that typically cause substance-related disorders Overview of Substance-Related Disorders Substance-related disorders involve drugs that directly activate the brain's reward system. The activation of the reward system typically causes feelings of pleasure; the specific pleasurable... read more or many others (eg, anticholinergics and corticosteroids may cause temporary psychotic syndromes). In addition, the mental disorder should

* Certain neurocognitive disorders caused by alcohol, inhalants, or sedative-hypnotics and perceptual disorders caused by hallucinogens may be long-lasting.

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NOTE: This is the Professional Version. CONSUMERS: Click here for the Consumer Version
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