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Substance Use Disorders


Mashal Khan

, MD, NewYork-Presbyterian Hospital

Reviewed/Revised Oct 2022 | Modified Nov 2022

Substance use disorders involve a pathologic pattern of behaviors in which patients continue to use a substance despite experiencing significant problems related to its use. Diagnosis of substance use disorder is based on diagnostic criteria for the pattern of behaviors. Treating substance use disorder is challenging and varies depending on the substance and circumstances.

The common terms "addiction," "abuse," and "dependence" have often been used with regard to substance use, but these terms are too loosely and variably defined to be very useful in systematic diagnosis. "Substance use disorder" is more comprehensive and has fewer negative connotations. The substances involved are members of the 10 classes of drug that typically cause substance-related disorders Overview of Substance Use .

Physiologic effects of substance use

These substances all directly activate the brain reward system and produce feelings of pleasure. The activation may be so intense that patients intensely crave the substance and neglect normal activities to obtain and use it. These substances also have direct physiologic effects, including

  • Intoxication

  • Withdrawal

  • Substance-induced psychiatric disorders

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 Psychiatric Disorders

For a psychiatric disorder 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 Use Substance-related disorders involve substances that directly activate the brain's reward system. The activation of the reward system typically causes feelings of pleasure; the specific characteristics... read more or many others (eg, anticholinergics and corticosteroids may cause temporary psychotic syndromes). In addition, the psychiatric disorder should

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

Clinical Approach to Substance Use Disorders

Use of illegal drugs, although problematic because it is illegal, does not always involve a substance use disorder. Conversely, legal substances, such as alcohol and prescription drugs (and cannabis in an increasing number of US states), may be involved in a substance use disorder. Problems caused by use of prescription and illegal drugs cut across all socioeconomic groups.

Recreational drug use, although often not sanctioned by society, is not a new phenomenon, and has existed in some form or another for centuries. People have used drugs for a variety of reasons:

  • To alter or enhance mood

  • As part of religious ceremonies

  • To obtain spiritual enlightenment

  • To enhance performance

Some users are apparently unharmed; they tend to use drugs episodically in relatively small doses, precluding clinical toxicity and development of tolerance and physical dependence. Many recreational drugs (eg, crude opium, alcohol, marijuana, caffeine, hallucinogenic mushrooms, coca leaf) are “natural” (ie, close to plant origin); they contain a mixture of relatively low concentrations of psychoactive compounds and are not isolated psychoactive compounds.

Etiology of Substance Use Disorders

People with a substance use disorder usually progress from experimentation to occasional use and then to heavy use and sometimes a substance use disorder. This progression is complex and only partially understood. The process depends on interaction between the drug, user, and setting.


Drugs in the 10 classes vary in how likely they are to cause a substance use disorder. The likelihood is termed addiction liability. Addiction liability depends upon a combination of factors including

  • Route of administration

  • Rate at which the drug crosses the blood-brain barrier and stimulates the reward pathway

  • Time to onset of effect

  • Ability to induce tolerance and/or withdrawal symptoms

In addition, substances that are legally and/or readily available (eg, alcohol, tobacco) are more likely to be used initially and thus increase the risk of progression to problematic use. Further, as perception of the risk in using a particular substance diminishes, there may be subsequent experimentation and/or recreational use of the drug, increasing exposures to substances of abuse. Fluctuations in perception of risk are influenced by multiple factors, including findings regarding medical and psychiatric sequelae of use and social outcomes.

During treatment of medical illness or following surgical or dental procedures, patients may be prescribed opioids Opioid Use Disorder and Rehabilitation “Opioid” is a term for a number of natural substances (originally derived from the opium poppy) and their semisynthetic and synthetic analogs that bind to specific opioid receptors. Opioids... read more . A substantial portion of these drugs go unused but may remain in the home, representing a significant source for children, adolescents, and adults who wish to use them for nonmedical purposes. In response, there has been increased emphasis on the need to

  • Prescribe opioid drugs in lower amounts more appropriate to the likely duration and severity of pain

  • Promote safe storage of leftover drugs

  • Expand prescription take-back programs


Predisposing factors in users include the following:

  • Psychologic characteristics

  • Circumstances and disorders

Psychologic characteristics are not clearly a strong factor, although people with low levels of self-control (impulsivity) or high levels of risk-taking and novelty-seeking may have an increased risk of developing substance use disorder. However, the concept of the addictive personality that has variously been described by some behavioral scientists has little scientific evidence to back it.

A number of circumstances and coexisting disorders appear to increase risk. For example, people who are sad, emotionally distressed, or socially alienated may find these feelings are temporarily relieved by a drug; this can lead to increased use and sometimes a substance use disorder. Patients with other, unrelated psychiatric disorders are at increased risk of developing a substance use disorder. Patients with chronic pain Chronic Pain Chronic pain is pain that persists or recurs for > 3 months, persists > 1 month after resolution of an acute tissue injury, or accompanies a nonhealing lesion. Causes include chronic disorders... read more (eg, back pain, pain due to sickle cell disease, neuropathic pain, fibromyalgia) often take opioid drugs for relief; many subsequently develop a substance use disorder. However, in many of these patients, nonopioid drugs and other treatments can adequately relieve pain and suffering.

Addiction is likely a polygenic disorder. There are a number of genetic and epigenetic factors that impact addiction progression. Research regarding specific genetic abnormalities varies by the specific substance.

Pearls & Pitfalls

  • The concept of the addictive personality has little scientific evidence to back it.


Cultural and social factors are very important in initiating and maintaining (or relapsing to) substance use. Observing family members (eg, parents, older siblings) and peers using substances increases risk that people will begin using substances. Peers are a particularly powerful influence among adolescents (see Drug and Substance Use in Adolescents Drug and Substance Use in Adolescents Substance use among adolescents ranges from sporadic use to severe substance use disorders. The acute and long-term consequences range from minimal to minor to life threatening, depending on... read more ). People who are trying to stop using a substance find it much more difficult if they are around others who also use that substance.

Physicians may inadvertently contribute to harmful use of psychoactive drugs by overzealously prescribing them to relieve pain or stress. Many social factors, including mass media, contribute to patients' expectation that drugs should be used to relieve all distress.

Diagnosis of Substance Use Disorders

  • Diagnostic criteria

Diagnosis of substance use disorder is based on identifying a pathologic pattern of behaviors in which patients continue to use a substance despite experiencing significant problems related to its use. The Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition, Text Revision (DSM5-TR) gives 11 criteria divided into 4 categories. Individuals meeting 2 or more of these criteria within a 12-month period are considered to have a substance use disorder.

Impaired control over use

  • The person takes the substance in larger amounts or for a longer time than originally planned

  • The person desires to stop or cut down on use of the substance

  • The person spends substantial time obtaining, using, or recovering from the effects of the substance

  • The person has an intense desire (craving) to use the substance

Social impairment

  • The person fails to fulfill major role obligations at work, school, or home

  • The person continues to use the substance even though it causes (or worsens) social or interpersonal problems

  • The person gives up or reduces important social, occupational, or recreational activity because of substance use

Risky use

  • The person uses the substance in physically hazardous situations (eg, when driving or in dangerous social circumstances)

  • The person continues to use the substance despite knowing it is worsening a medical or psychologic problem

Pharmacologic symptoms

  • Tolerance: The person needs to progressively increase the drug dose to produce intoxication or the desired effect, or the effect of a given dose decreases over time

  • Withdrawal: Untoward physical effects occur when the drug is stopped or when it is counteracted by a specific antagonist

The severity of the substance use disorder is determined by the number of symptoms:

  • Mild: 2 to 3 criteria

  • Moderate: 4 to 5 criteria

  • Severe: 6 criteria

Treatment of Substance Use Disorders

  • Varies depending on substance and circumstances

Treating substance use disorder is challenging and includes one or more of the following:

  • Acute detoxification

  • Prevention and management of withdrawal

  • Cessation (or rarely, reduction) of use

  • Maintenance of abstinence

With increasing evidence and greater understanding of the biologic processes underlying compulsive drug-taking, substance use disorders have become much more firmly established as medical illnesses. As such, these illnesses are amenable to various forms of treatment, including support groups (Alcoholics Anonymous and other Twelve Step programs); psychotherapy (eg, motivational enhancement therapy, cognitive-behavioral therapy, relapse prevention); and medications, ranging from agonist therapy (eg, nicotine replacement therapy for tobacco use disorder, methadone and buprenorphine for opioid use disorder) to novel approaches currently under investigation. Focus on accurate identification of patients with substance use disorders and referral for specialty treatment will help greatly in reducing individual consequences as well as societal impact.

Key Points

  • Substance use disorder involves a pathologic pattern of behaviors in which patients continue to use a substance despite experiencing significant problems related to its use.

  • Manifestations are categorized into impaired control over use, social impairment, risky use, and pharmacologic symptoms.

  • The terms "addiction," "abuse," and "dependence" are vague and value-laden; it is preferable to speak of "substance use disorders" and focus on the specific manifestations and their severity.

  • The consequences and treatment of substance use disorder vary greatly depending on the substance.

Drugs Mentioned In This Article

Drug Name Select Trade
Cafcit, NoDoz, Stay Awake, Vivarin
Commit, Habitrol, Nicoderm CQ, NICOrelief , Nicorette, Nicotrol, Nicotrol NS
Dolophine, Methadose
Belbuca, Brixadi, Buprenex, Butrans, Probuphine, Sublocade, Subutex
NOTE: This is the Professional Version. CONSUMERS: View Consumer Version
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