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seeking information on Alcohol Dependence (Alcoholism) and a sense of community through our Discussion Forums.

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Alcohol Dependence (Alcoholism) and the Brain

By: S. Rennie, LPN

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Alcohol and alcohol dependence (alcoholism) can affect the brain and behavior in a variety of ways, and multiple factors can influence these effects. About half of the nearly 20 million people with alcohol dependence in the United States seem to be free of cognitive impairments. However, the remaining half has neuropsychological difficulties ranging from mild to severe.1 It is estimated that two million will develop permanent and debilitating conditions that require lifetime custodial care.1 Alcohol-related brain injury is more likely to occur if a person drinks heavily on a regular basis over many years but also likely to occur over a short period of time if the drinker is aggressive enough. This can be known as 'binge drinking', which means drinking more than six drinks at a time.2

Difficulty walking, blurred vision, slurred speech, slowed reaction times, impaired memory are clearly alcohol effects on the brain.3 Some are noticeable after only one or two drinks and will resolve once drinking has stopped.3 Over the long term, a person who drinks heavily may have brain deficits that persist well after he or she achieves sobriety. Heavy drinking may have extensive and far-reaching effects on the brain, ranging from simple memory 'slips' to permanent and debilitating conditions that require lifetime custodial care.3

There are a wide range of variables that influence the effects of alcohol dependence on the brain.1 These include the amount of alcohol consumed, the age the person began drinking, duration, current age, education level, gender, genetic background and family history of alcohol dependence.1,3

Blackouts: The effects of alcohol can be detected after only a few drinks and, as the alcohol increases, so does the degree of impairment.3 Large quantities of alcohol, especially when consumed quickly and on an empty stomach, can produce a blackout, or an interval of time that the person cannot recall details either partially or in their entirety.3

Thiamine Deficiency: A common occurrence in people with alcohol dependence and results in overall poor nutrition.3 This is an essential nutrient required by all tissues including the brain. It's also known as B1. About 80 percent of people with alcohol dependence have a deficiency in this nutrient and will develop serious brain disorders, such as Wernicke-Korsakoff syndrome.3 This is explored in its entirety in the health section:

Alcohol-Related Brain Injury: Brain injuries can be caused by alcohol because it:2

  • Has a toxic effect on the central nervous system.
  • Results in changes to metabolism, heart function and blood supply.
  • Interferes with B1 (thiamine) absorption, an important brain nutrient.
  • May be associated with poor nutrition.
  • Can cause dehydration, which can lead to wastage of brain cells.
  • Can lead to falls and accidents that injure the brain.

Alcoholic Encephalopathy: Alcohol's harmful effects on liver cells not only interfere with the normal functioning of the liver but also impact distant organs, including the brain. Normal brain functioning depends on several aspects of normal liver functioning. The liver supplies certain nutrients to the brain that the brain itself cannot produce as well as cleansing the blood of substances that could damage brain cells.4 Prolonged liver dysfunction resulting form excessive alcohol consumption can lead to the development of this serious and potentially fatal disease.4 Symptoms of this can be sleep disturbance, changes in personality and mood, shortened attention span and other cognitive effects, anxiety and depression, tremors, as well as other motor deficits.4 In the most serious of cases the person can fall into a coma when they no longer respond to stimuli.4

Other disorders associated with alcohol are changes in memory and thinking abilities (cognition), difficulties balance and coordination and a range of medical and neurological disorders.2 The disorders are:

  • Cerebellar atrophy: area of the brain responsible for muscle coordination. Damage results in difficulties with balance and walking, called ataxia.2
  • Frontal lobe dysfunction: area of the brain involved in abstract thinking and planning. Damage results in cognitive difficulties.2
  • Peripheral Neuropathy: the extremities are affected my numbness, pain, pins and needles.2


  1. Marlene Oscar–Berman, Ph.D., and Ksenija Marinkovic, Ph.D. Alcoholism and the Brain: An Overview. National Institute on Alcohol Abuse and Alcoholism Publication. July, 2004.
  2. ARBIAS. Alcohol related brain damage. Better Health Channel. Victorian (Australian) Government. June, 2006.
  3. NIAAA Alcohol Alert: Alcohol's Damaging Effects on the Brain. Number 63, October, 2004.
  4. Roger F. Butterworth, Ph.D., D.Sc. Hepatic Encephalopathy – A Serious Complication of Alcoholic Liver Disease. National Institute on Alcohol Abuse and Alcoholism Publication. July, 2004.

This page was last modified on : 10/28/2013

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