Signs and Symptoms of Intoxication

Alcohol is absorbed by the small intestine into the bloodstream. The blood then enters the liver, where most of the alcohol is metabolized. The body excretes a small amount of unprocessed alcohol. The body absorbs alcohol more quickly than it metabolizes, so the blood alcohol concentration increases quickly and effects occur rapidly.

Bottle Alcohol Image - Masterfile

Alcohol is a central nervous system depressant. In general, the first noticeable effects of alcohol—reduced anxiety, sedation—occur when blood alcohol concentration is at 0.04 gr per 100 mL of blood. As blood alcohol levels rise, the person may show the following signs:

  • Confusion
  • Coordination difficulties
  • Expansive mood
  • Impaired memory
  • Poor judgment
  • Sense of well-being
  • Short attention span
  • Slurred speech
  • Talkativeness

On average, between three and six standard drinks cause legal intoxication, which, depending on state laws, is defined as blood alcohol concentration of 0.08 gr or 0.10 gr per 100 mL of blood.

When blood alcohol levels fall, the person experiences symptoms such as being withdrawn, sedate, and/or depressed. Eventually, the body metabolizes and excretes the alcohol and the person sobers up.

Very high levels of blood alcohol cause the person to fall asleep or pass out. More rarely, severe intoxication caused by alcohol poisoning is life threatening:

  • At .40 BAC, alcohol suppresses the cardiorespiratory system. Coma or death may result.
  • At .45 BAC, alcohol suppresses major organ systems. Death results.

Several factors, such as the amount of alcohol consumed, body weight, and food intake, affects the rate at which a person becomes intoxicated. Water content also affects the rate at which alcohol is metabolized: the higher the water content, the more alcohol absorbed. Women, whose bodies typically have a higher percentage of water content, show signs of intoxication more quickly.

Signs and Symptoms of Alcohol Tolerance

Tolerance occurs when a person's body is less responsive to alcohol because of repeated exposure. Alcohol causes neurons (nerve cells) in the central nervous system to adapt to its presence. Those who are tolerant require more alcohol to produce an effect, such as reducing anxiety.

In addition, liver enzymes that detoxify alcohol increase with frequent drinking; thus, the liver of an alcoholic breaks down alcohol more quickly than it did when first exposed to alcohol, contributing to the development of tolerance. Tolerance levels can increase to the point that a long-term alcoholic can consume a quantity of alcohol that would be extremely dangerous to a nondrinker.

Signs and Symptoms of Alcohol Abuse

Abuse is characterized by frequent drinking that causes the person to neglect responsibilities such as working, caring for children, or attending school. Difficulties with family, friends, and coworkers because of drinking are also signs of abuse. The person may drink when it is dangerous, for example while driving. It is common for those who abuse alcohol to have legal problems related to drinking, such as being arrested for disorderly conduct. Abuse may lead to dependence.

Signs and Symptoms of Alcohol Withdrawal

In clinical withdrawal, two or more of the following symptoms occur several hours or up to a few days after someone stops drinking:

  • Anxiety
  • Autonomic hyperactivity (i.e., sweating, pulse rate greater than 100)
  • Delirium tremens (i.e., anxiety, increased heart rate, sweating, trembling, confusion)
  • Difficulty performing tasks involving coordination
  • Grand mal seizures (i.e., convulsions resulting in loss of consciousness and muscle contractions)
  • Hallucinations (sights, sounds, or physical sensations on the skin, elevated or decreased temperature)
  • Hand tremor
  • Insomnia
  • Nausea, vomiting

Symptoms vary in incidence and severity, and usually subside within hours or a few days. The risk for symptoms depends on drinking patterns, coexisting illnesses, genetic factors, and the make-up of the person's central nervous system. In general, larger amounts of alcohol correlate with more severe symptoms. Medical attention may be necessary to prevent serious complications. Chronic alcoholism causes vitamin deficiencies, particularly vitamin B, which contributes to withdrawal symptoms.

Signs and Symptoms of Alcohol Dependence

People who are alcohol dependent are unable to reduce the amount they drink or to stop drinking, though they often try. Most telling, alcohol use takes over more and more of the person's life, and he or she may deny the complications it causes. Those who are dependent often experience physical and psychological dependence. Psychological dependence is characterized by the belief that alcohol is necessary in order to perform everyday activities. Dependence is confirmed when alcohol use is accompanied by signs of tolerance, withdrawal, abuse, and the compulsion to drink even when there are clear signs that it interferes with daily life.

Publication Review By: Debra Emmite, M.D., Stanley J. Swierzewski, III, M.D.

Published: 02 Apr 2001

Last Modified: 28 Aug 2015