• Clinical science

Alcohol use disorder


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

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

Legal intoxication levels of BAC is between 0.08–0.15% (depending on state laws).

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

Alcohol withdrawal

Minor withdrawal

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

Withdrawal seizures

Alcoholic hallucinosis

  • Onset: 12–48 hours of last alcoholic beverage
  • Clinical features
    • Consciousness usually intact
    • Normal vital signs
    • Hallucinations (both auditory and/or visual are common; , but also tactile is possible) and delusions
  • 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 abrupt cessation of alcohol use
  • 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 seizures
    • Stronger monosynaptic and polysynaptic reflexes
    • 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



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 is 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 planned
    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 aggressive behavior

  • Benzodiazepines and typical antipsychotics (e.g., haloperidol) as sedation
  • Mechanical restraints may be used for individuals who pose a danger to themselves and/or others and when previous de-escalation and medication strategies were unsuccessful.

Managing alcohol intoxication

  • Mild: mainly supportive
  • Moderate: IV hydration and correction of electrolyte disturbances
  • Severe
    • Frequent monitoring
    • Aggressive fluid therapy
    • IV thiamine infusion to prevent or treat Wernicke's encephalopathy
    • Exclude occult trauma (e.g., imaging), if suspected

Managing withdrawal


Haloperidol may worsen respiratory depression secondary to alcohol intoxication!





In pregnancy

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