Merck Manual

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Substance-Induced Disorders


Thomas Kosten

, MD, Baylor College of Medicine/MD Anderson Cancer Center

Last full review/revision Oct 2018| Content last modified Oct 2018
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Substance-induced disorders are a type of substance-related disorder that involve the direct effects of a drug; they include

  • 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. 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 syndrome must cause the patient significant distress and/or impair functioning (eg, social, occupational). Most patients with withdrawal recognize that re-administering the substance will reduce their symptoms.

Although some patients with a withdrawal syndrome have a substance use disorder, some drugs, particularly opioids, sedative/hypnotics, and stimulants, can result in withdrawal symptoms even when taken as prescribed for legitimate medical reasons and for relatively brief periods (< 1 wk for opioids). Withdrawal symptoms that develop following appropriate medical use are not considered criteria for diagnosis of a substance use disorder.

Substance-induced mental disorders

Substance-induced mental disorders are mental changes produced by substance use or withdrawal that resemble independent mental disorders (eg, depression, psychosis, anxiety, or neurocognitive 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 or many others (eg, anticholinergics and corticosteroids may cause temporary psychotic syndromes). In addition, the mental disorder should

  • Appear within 1 mo of substance intoxication or withdrawal

  • Cause significant distress or impaired functioning

  • Not have manifested before use of the substance

  • Not occur solely during acute delirium caused by the substance

  • Not persist for a substantial period of time*

*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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