Is Alcoholism Genetic? Causes of Alcohol Addiction

alcohol with fighting couple

The question, “Is alcoholism hereditary?” is asked frequently. The links between alcoholism, genetics and family history are complex. Research has yielded strong evidence pointing to a familial connection. Youth who start drinking before age 15 are six times more likely to develop alcohol dependence or abuse later in life than those who begin drinking at or after age 21.1 Children with parents addicted to alcohol are three to four times more likely than their peers to become addicted to alcohol.2 So although having one or two alcoholic parents greatly increases one’s risk, it is not an absolute certainty a child of alcoholics will develop these problems.

What Is an Alcoholic?

A universal definition of what it means to be an alcoholic does not exist. One definition is as follows: An alcoholic is a person who suffers from alcoholism, exhibiting a distinct physical desire to consume alcohol beyond their capacity to control it, regardless of all rules of common sense.3

An alcoholic displays at least two of the four characteristics of alcoholism, as follows:

Craving: Typically, an alcoholic obsesses about alcohol from morning until night. Their entire existence resolves around an uncontrollable relationship with and craving for alcohol.4

Loss of control: An alcoholic is unable to have just one or two drinks. Eventually, the addicted drinker may lose control over many aspects of his or her life. As drinking gets worse, so does the alcoholic’s ability to perform basic tasks such as paying bills, keeping appointments and meeting family and work obligations.4

Physical dependence: The brain and body become physically reliant on alcohol. Over time, regular alcohol consumption can disrupt the balance of the brain neurotransmitter GABA, which controls impulsiveness, as well as glutamate, which stimulates the nervous system. Brain levels of dopamine increase with alcohol consumption, which may cause drinking to be more pleasurable. When a person stops drinking, this elicits alcohol-specific physical and mental symptoms, some of which can be life-threatening.4,5

Tolerance: Developing a tolerance to alcohol means it takes more to produce the same effect. A growing body of research from the University of California, San Diego pinpointed inherent tolerance or low sensitivity to drinking in people with a family history. Ironically, low-sensitivity actually increases the risk of a person becoming an alcoholic.4,5

You don’t have to be an alcoholic to suffer the many consequences of heavy drinking. Anyone who regularly consumes alcohol in excessive amounts can eventually develop moderate, severe or life-threatening side effects. Research shows students who engaged in repeated episodes of binge drinking were more likely than other students to experience memory impairment when intoxicated.6 Excessive alcohol consumption and binge drinking negatively impact many bodily systems and functions, making one vulnerable to specific types of cancer and more prone to involuntary and intentional injuries.7

Drinking Is a Choice

The decision to take a first drink is not dictated by one’s genes. Rather, it is influenced by environment, social situations, friends and peers, family members and availability and access to alcohol. Once a person has imbibed for the first time, whether this develops into problem drinking is tied to a greater extent on genetics and family history. If you have a family history of alcoholism, you can choose to never try alcohol, reducing the risk of becoming an alcoholic to zero.

Family History of Problem Drinking

There is no single cause of alcoholism. Like other chronic and complex diseases, it is often caused by a variety of factors including the age at which you started drinking and your mental health and social or cultural factors — such as having a spouse who drinks a lot. The most important risk factor for reliably predicting alcoholism is family history. Even without analyzing the genes involved, research clearly indicates this chronic disease runs in families.

Genetics and Alcoholism

To better understand the strong connection between problem drinking and family history, researchers have analyzed genes that may be implicated in alcoholism. Some diseases are caused by a single genetic defect.  For example, one gene has been deleted or a gene mutation occurs. Confounding social, economic and cultural factors, as well as a family history of drinking, make pinpointing a genetic connection difficult. However, animal and human research studies have yielded promising results that one day could lead to preventive and treatment strategies.

A genetic variant common in people from East Asia (such as China, Japan and Korea) impairs production of an enzyme that helps metabolize alcohol in the liver. As a result, acetaldehyde (a toxic byproduct of alcohol) is not broken down into harmless acetic acid, but builds up in the blood and liver. This gene variant causes flushing in the face, neck and sometimes the shoulders and entire body, although it has more serious health implications. A 2013 study found middle-aged Korean “flushers” who consumed more than four drinks a week were twice as likely to develop hypertension as non-flushers who drank the same amount. Similarly, a 2012 study found Chinese people with the genetic variant were at elevated risk of hypertension if they drank.8

A mouse model study identified a gene called Nf1 (neurofibromatosis type 1). This regulates a signaling pathway linked to alcohol dependence by affecting the production of the neurotransmitter GABA. Researchers looked at the amount of GABA released by a region of the brain called the central amygdala. Analyzing genetic data from 9,000 people for a variation in Nf1, they found an association between Nf1 and the onset and severity of alcoholism. The study suggests the possibility of future genetic testing to assess who is at risk of developing alcohol addiction.9

Researchers used whole-genome sequencing to analyze the genetic signatures of two lines of rats. One line was bred to consume large amounts of alcohol, possessing many characteristics of human alcoholism, while the other was bred to consume small amounts of alcohol. By comparing the genomes of both rat lines, the researchers identified areas of genetic code in 930 genes linked to a preference for alcohol. Many of the genetic codes associated with alcohol preference were located in single gene regions, primarily promoters and introns, which are areas that either bolster or regulate gene activity. If these findings can be verified in humans, this could lead to genetic and neurological-based treatments for alcoholism.10

While the mechanisms in which genes impact the likelihood of alcohol addiction are complex, they clearly play an intrinsic role. If you have a family history of alcoholism, you are not destined to follow in your parents’ footsteps. Abstaining altogether is the safest option for anyone with a genetic predisposition to alcoholism or problem drinking.

  1. Fact Sheets – Underage Drinking. Centers for Disease Control and Prevention website. Updated October 20, 2016. Accessed December 14, 2016.
  2. Effects of Parental Substance Abuse on Children and Families. American Academy of Experts in Traumatic Stress website. Accessed December 14, 2016.
  3. What Is An Alcoholic? How To Treat Alcoholism. Medical News Today website. Updated September 5, 2016. Accessed December 14, 2016.
  4. Alcoholism Definition. Alcoholism Guide website. Accessed December 14, 2016.
  5. Klein S. Ask Healthy Living: What Is Alcohol Tolerance? Huffington Post. March 17, 2014. Accessed December 14, 2016.
  6. What Happened? Alcohol, Memory Blackouts, and the Brain. National Institute on Alcohol Abuse and Alcoholism website. Published July 2004. Accessed December 14, 2016.
  7. Alcohol’s Effects on the Body. National Institute on Alcohol Abuse and Alcoholism website. Accessed December 14, 2016.
  8. Asians and Alcohol. Berkeley Wellness website, Published July 24, 2014. Accessed December 14, 2016.
  9. Haiken M. Forbes August 27, 2014. Accessed December 14, 2016.
  10. Alcoholism influenced by hundreds of genes, study finds. Published August 5, 2016. Accessed December 14, 2016.
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