• Clinical science

Alcohol use disorder (Alcohol dependence syndrome)


Alcohol use disorder (AUD) is a common condition in the US that affects both adults and adolescents. It is characterized by a pattern of alcohol use that leads to clinically significant impairment or distress, as manifested by psychosocial, behavioral, or physiologic features. Patients may also present with acute alcohol intoxication or features of alcohol withdrawal. Diagnosis of AUD begins with screening guided by the AUDIT-C or CAGE test and is then categorized as mild, moderate, or severe based on the number of DSM-5 criteria fulfilled. Laboratory tests, such as carbohydrate-deficient transferrin (CDT) test, and transaminase levels, may confirm the presence of alcohol use if a vague history is provided. Treatment may include fluid therapy, benzodiazepines, and thiamine replacement, depending on the presentation. Long-term management consists of psychosocial counseling and pharmacotherapy to prevent relapse. Complications of AUD include seizures, features of chronic thiamine deficiency (e.g., Wernicke-Korsakoff syndrome), and fetal alcohol syndrome in pregnancy.


  • Alcohol consumption is associated with > 3 million deaths worldwide per year.
  • Prevalence: 13.9%; more common in Native Americans
  • Sex: > 2:1
  • Peak incidence: 21–34 years
  • Associated comorbidities


Epidemiological data refers to the US, unless otherwise specified.



Clinical features

  • Features of mild, moderate, or severe alcohol use disorder (see the DSM-V criteria in the “Diagnostics” section; ), including tolerance and dependence (see “Substance-related and addictive disorders)
  • Features of acute alcohol intoxication
  • Features of alcohol withdrawal

Subtypes and variants

Acute alcohol intoxication

  • Definition: : a temporary condition in which excessive consumption of alcohol results in alterations in a person's consciousness, cognition, perception, judgment, affect, or behavior
  • Pathophysiology: Most alcohol is absorbed into the blood by the proximal small intestine (only small amounts of alcohol enter the body through mucous membranes such as the mouth, the esophagus, and the stomach). .
  • Clinical Features
Mild intoxication (Blood alcohol concentration (BAC) 0.01–0.1%, < 100 mg/dL) Moderate intoxication (BAC 0.15–0.3%) Severe intoxication (BAC above 0.3%, > 300 mg/dL)
  • Increased agitation, euphoria (disinhibition, urge to speak), impaired judgment
  • Unsteady gait and difficulties standing upright
  • Skin flushing
  • Mild tachycardia
  • Pronounced disinhibition
  • Significant reduction of attention, responsiveness, alertness, and reaction time
  • Impaired vision and sound localization
  • Increasing unsteadiness of gait and slurred speech
  • Dizziness or psychomotor agitation
  • Nausea and vomiting
  • Amnestic gaps
  • Delusions and hallucinations
  • Severe dysarthria, dizziness, ataxia
  • Transition to alcoholic coma (usually occurs at BAC levels between 0.40–0.50%) including:
    • Severely impaired consciousness
    • Lack of defensive reflexes
    • Respiratory depression

In the USA, the legal limit for driving under the influence of alcohol is a BAC of 0.08%

Vital functions of intoxicated individuals may deteriorate due to the relatively long absorption time of alcohol (approx. 40 minutes).

Alcohol withdrawal

  • Alcohol withdrawal syndromes occur following a reduction in alcohol use after a prolonged period of excessive drinking
  • Onset and duration vary amongst the different syndromes (see below for details)

Hospitalized patients with chronic alcohol abuse who must abstain from alcohol can develop alcohol withdrawal syndromes within the first couple of days of inpatient care!

Minor withdrawal

  • Onset: 6–36 hours after last drink
  • Clinical features
  • Resolves within 24–48 hours

Withdrawal seizures

Alcoholic hallucinosis

  • Onset: 12–48 hours after last drink
  • Clinical features
  • Usually resolves 24–48 hours after onset

Alcohol hallucinosis can be confused with schizophrenia because both present with hallucinations!

Delirium tremens

  • Definition: Persistent alteration of consciousness and sympathetic hyperactivation due to alcohol withdrawal.
  • Onset: most commonly occurs within 48–96 hours after last drink
  • Clinical features
    • Impaired consciousness, disorientation
    • Visual hallucinations (usually small, moving objects, e.g., white mice)
    • Increased suggestibility
    • Rest and intention tremor (first high-frequencylow-frequency), sweating, nausea
    • Tachycardia, hypertension
    • Generalized tonic-clonic seizures
    • Hyperreflexia
    • Possible death
  • Persists for 1–5 days

In individuals with chronic alcohol use, withdrawal delirium is caused by too little rather than too much alcohol!

Alcoholic ketoacidosis

  • Definition: elevated anion gap metabolic acidosis due to increased production of ketone bodies with normal or low glucose levels. Most commonly occurs in malnourished patients with alcohol use disorder.
  • Etiology: occurs in patients with alcohol use disorder after an episode of recent binge drinking followed by abrupt cessation of drinking
  • Pathophysiology: accumulation of ketone bodies as a result of:
    • Increased lipolysis and free fatty acid release due to:
    • Volume depletion; (e.g., vomiting or poor oral fluid intake) → impaired renal perfusion → decreased ability to excrete ketone bodies
  • Clinical features
  • Diagnostics
  • Treatment
  • Prognosis: reversible with appropriate treatment



Diagnosis of AUD begins with a screening test, which is followed by a confirmatory test based on medical history.


  • AUDIT-C test
    • Includes three questions based on the Alcohol Use Disorders Identification Test (AUDIT), see table below
    • Evaluation
      • Every response is given a score from 0 to 4 points
      • Total score is from 0 to 12
      • Positive test (meaning the presence of an alcohol use disorder) is:
        • ≥ 4 in men
        • ≥ 3 in women
Question Response Score
“How often did you have a drink containing alcohol in the past year?” Never 0
≤ Monthly 1
2–4 times a month 2
2–3 times a week 3
≥ 4 times a week 4
“How many drinks did you have on a typical day when you were drinking in the past year?” 1–2 0
3–4 1
5–6 2
7–9 3
≥ 10 4
“How often did you have ≥ 6 drinks on one occasion in the past year?” Never 0
< once per month 1
Monthly 2
Weekly 3
Daily or almost daily 4
  • CAGE test
    • A series of four questions used to screen for alcohol use disorder, includes:
      1. C: Cut down drinking: “Have you ever felt you should cut down on your drinking?”
      2. A: Annoyed: “Have people annoyed you by criticizing your drinking?”
      3. G: Guilty: “Have you ever felt guilty about drinking?”
      4. E: Eye-opener: “Have you ever felt you needed a drink first thing in the morning (eye-opener) to steady your nerves or to overcome a hangover?”
    • Every “yes” response gives a score of one point.
    • Evaluation: The test is considered positive for alcohol use disorder if ≥ 2 questions are answered in the affirmative.

Confirmatory tests

DSM-V criteria

  • Patients who screen positive are assessed using 11 criteria based on patient history. A diagnosis is made for ≥ 2 criteria are positive.
    1. Drinking more or longer than intended
    2. Tried to cut down or stop more than once, but couldn't
    3. Spends a lot of time drinking
    4. Wanting a drink so badly that the patient couldn't think of anything else
    5. Drinking has a negative impact on everyday function (social, work etc)
    6. Continued drinking despite the knowledge of its harmful effects
    7. Given up interests that were important because of drinking
    8. Drinking has increased their risk behavior more than once
    9. Continued drinking despite health problems or blackouts
    10. Increasing amount of drinks to maintain same effects as before
    11. Features of withdrawal when the effects of alcohol were wearing off
  • Severity
    • Mild: presence of 2–3 symptoms
    • Moderate: presence of 4–5 symptoms
    • Severe: presence of 6 or more symptoms

Laboratory tests



Managing agitation or aggression

  • Sedation with benzodiazepines or typical antipsychotics (e.g., haloperidol)
  • Mechanical restraints may be used for individuals who pose a danger to themselves and/or others when previous de-escalation and medication strategies have been unsuccessful.

Managing alcohol intoxication

Managing withdrawal


Haloperidol may worsen respiratory depression secondary to alcohol intoxication!





In pregnancy

We list the most important complications. The selection is not exhaustive.

last updated 10/18/2019
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