Overall, family, adoption,3 and twin studies provide convergent evidence that hereditary factors play a role in alcohol dependence, with variations in genes estimated to account for 50 to 60 percent of the total variance in risk. Several study designs, including twin, family, and adoption studies, are used to determine whether relatively common diseases, such as alcohol dependence, are caused at least in part by genetic factors and to estimate the magnitude of the overall genetic contribution. Early genetic studies were focused on delineating whether environmental factors, genetic factors, or both contributed to the risk for alcohol dependence. Twin, adoption, and family studies conclusively demonstrated that genetic factors account for 50 to 60 percent of the variance in risk for developing alcoholism. In the largest study of genetic factors linked to alcohol dependence, an international team of researchers identified a gene known to affect risk and determined that many other genes also contribute to risk for alcohol dependence to a lesser degree.
The NSDUH reports that more than 14 million people aged 12 and older had an AUD in 2017, with AUD occurring in 7% of males and 3.8% of females aged 12 and older.4 According to the 2017 National Survey on Drug Use and Health (NSDUH), 51% of the population aged 12 and older reported binge drinking in the past month. For men, this low-risk range is defined as no more than 4 drinks on a given day and no more than 14 per week. According to the National Institute on Alcohol Abuse & Alcoholism (NIAAA), women who have no more than 3 drinks on a given day and no more than 7 per week are at low-risk for developing AUD.
Alcohol dependence, psychiatric disorders share genetic links
This suggests that even if you’ve been separated from your biological relatives, a genetic history of alcohol abuse still has an impact. In other words, psychology and home environment likely have a significant impact on how alcoholism is passed down through families. Can your genes really determine if you become addicted to alcohol? Adoption studies compare the disease status of adoptees with that of their birth parents (with each of whom they share on average half their genome) and of their adoptive parents (with whom they typically have no genetic relationship and do not share their genome).
However, having these genetic traits does not guarantee you will develop alcoholism; environmental and personal choices also play a critical role. AUD affects millions of people, and its causes can be traced to a mix of genetic, environmental, and social factors. One of the most common questions people ask is, Is alcoholism genetic? “It is important to include individuals from different ancestral backgrounds in genetic studies because it provides a more complete understanding of the genetic basis of alcohol behaviors and other conditions, all of which contributes to a more inclusive and accurate understanding of human health,” she said. Genetics can account for about 40-60% of the risk for alcoholism, but environmental and lifestyle factors also play a significant role. This highlights the complexity of shared genetic and lifestyle risks, as both factors often coexist and reinforce each other within families.
Teasing these effects apart is challenging, and to date fewer than a dozen genes that influence one’s risk for alcoholism have been identified, although more surely exist. Identifying genetic influences on vulnerability to alcohol addiction can lead to more targeted treatments and help those at risk to make informed choices about their own lives In a sample of families densely affected by alcohol use disorder, we found evidence for genetic nurture effects. This pattern of effects is consistent with prior evidence that there are overlapping sets of genetic influences that contribute to alcohol problems, relationship discord, and divorce22, and indicates that even nontransmitted alleles influence offspring alcohol outcomes via parental relationship discord. Using extended nature of nurture methods, we examined parental relationship discord and parental divorce as mechanisms through which genetic risk for alcohol problems is transmitted in families. Among EA participants, there was evidence that both transmitted and nontransmitted alleles had indirect genetic effects on offspring AUDSx, Max Drinks, and Initiation through the corresponding parental alcohol phenotypes.
Specific Genes and Variants
Environmental influences may also prevent the expression of their inherited genes. This could be because not everyone inherits their parent’s genes linked to AUD. Environmental factors, such as upbringing, can also increase the risk of AUD.
Understanding alcoholism
Psychological factors such as certain personality traits, stress responses, and co-occurring mental health conditions also influence AUD. Alcohol use disorder (AUD) is a chronic condition with serious effects on individuals and society. Even those who survive can suffer irreversible brain damage from a sustained lack of oxygen delivery.14 People who have an AUD are at an increased risk of alcohol poisoning.7 Alcohol poisoning can occur when you ingest too much alcohol too quickly (as with rapid binge drinking), resulting in very high blood alcohol levels that impair brain control of vital functions such as breathing, heart rate, and body temperature, resulting in death.14 Beyond that, Palmer and his team want to develop a better understand of how the genes they’ve identified might influence these traits, but using animal and cellular models. “In fact, using this questionnaire in a population not ascertained for alcohol use disorders we have been able to achieve the largest sample size even obtained in the field of alcohol use disorders,” said Sanchez Roige.
We also think the genetic susceptibility to alcohol dependence stems from the small, cumulative effects of a very large number of variants across the genome.” The effects of other genes weren’t big enough to reach statistical significance individually — even though this study involved more than 50,000 people — but their combined effects were significant. The new analysis, from the Substance Use Disorders working group of the Psychiatric Genomics Consortium, adds to the current understanding of alcohol dependence, a complex disorder influenced by genes, environment and their interactions. If you are still unsure about your situation, it may be best to talk to a mental health professional who specializes in alcohol addiction treatment or substance abuse disorder.
Family behavior and drinking patterns
The study is also important because of the massive health and socio-economic impacts of substance abuse in general. The researchers used a questionnaire completed by participants to differentiate problem drinking from casual alcohol consumption, an important distinction in this study. Researchers in this study found an overlapping association between alcohol abuse and psychiatric conditions such as depression, attention-deficit disorder, and schizophrenia. Psychological, social, and environmental factors also influence the likelihood of developing the addiction. Other genetic factors how to store pee for drug test and environment likely play a bigger role than any single gene in whether or not a person develops AUD.
Candidate Gene Studies and Gene Targeting
Family dynamics, beyond mere drinking habits, can also contribute to the development of AUD. Teenagers who spend time with peers who drink are more likely to engage in alcohol use themselves, often as a means of fitting in and gaining social acceptance. Children who witness parents or caregivers drinking regularly, often to cope with stress or celebrate occasions, may internalize this behavior as acceptable and even necessary.
Studies suggest that genetic factors account for about 40-60% of the risk for developing AUD. By fostering healthy environments, modeling positive behaviors, and providing adequate support, families can significantly reduce the risk of addiction in their children. In conclusion, while genetics play a role in the likelihood of becoming an alcoholic, upbringing is a powerful determinant in whether that genetic potential is realized.
For example, researchers consistently have observed low levels of the neurotransmitter serotonin in certain brain areas (i.e., the limbic system) and other indications of dysregulation of the serotonin system in animal lines bred for high alcohol drinking (Crabbe 2008). Studies with these selected lines have contributed a great deal to understanding the neurobiological bases for alcohol’s myriad effects. Animals have been selected for many alcohol-related traits, including preference for alcohol, tolerance or sensitivity to alcohol’s effects, and withdrawal severity. In 1959, inbred mouse strains first were shown to differ in their tendency to drink alcohol (McClearn and Rodgers 1959), and studies with inbred strains continue to this day. This sample included both African-American and European-American subjects, and the primary analysis sought to identify association with alcohol dependence using a case–control design.
Cultural norms and attitudes towards alcohol vary widely across societies and communities. This chronic stress can increase the likelihood of turning to alcohol as a coping mechanism. Socioeconomic status (SES) plays a significant role in alcohol accessibility and consumption patterns. However, this temporary relief often leads to a dangerous cycle of dependence and worsening mental health. Children who experience trauma, abuse, or witness domestic violence are at a heightened risk of developing AUD later in life.
- Predictors in the parent generation included relationship discord, divorce, alcohol measures parallel to those in the child generation, and polygenic scores for alcohol problems.
- Together, these approaches, although by no means completed, already have resulted in the identification of some genes that impact the risk for alcohol dependence.
- Similar to the GABA-A receptors, the genes encoding these receptors are found in clusters on several chromosomes.
- The researchers found that the genetic risk factors related to alcohol dependence also were linked to risk for other psychiatric disorders, such as depression, schizophrenia, ADHD and the use of cigarettes and marijuana.
- Children of people with AUD have a significantly higher risk of developing the disorder.
An exploratory factor analysis (EFA) on the five items related to children’s perceptions of parental relationship discord was conducted to inform the calculation of the parental relationship discord composite. SNPs where parental origin was ambiguous (e.g., an offspring C/T SNP for parents who are C/T heterozygotes) were removed from the PRS calculation. Following the calculation of the posterior effect sizes, additive polygenic scores were calculated for transmitted and nontransmitted alleles for mothers and fathers, separately. Imputed genotypes for the COGA parent-offspring trios, in combination with summary statistics from independent GWAS discovery samples, were used to construct the genome-wide polygenic risk scores using PRS-CSx41. Similar to other recent studies37–40 we used 10 ancestry principal components as covariates.
- Other research has revealed that the same variation in the same gene as occurs in Europeans also influences risk in people of Asian descent, but that data was not included in this study.
- Key alcoholism gene influences how quickly body metabolizes alcohol
- Many individuals with a family history of substance abuse can choose sobriety or moderate alcohol use with the right support.
- Alcoholism can impact multiple generations, but the cycle isn’t inevitable.
- Consuming alcohol alters the amount of GABA available to the brain.
- As you increase the number of times you drink, you will also need to increase the amount of alcohol you drink.
Developing alcohol tolerance can be a sign of an alcohol use disorder. When you first start drinking alcohol, you may feel happy, confident, friendly, and euphoric after a few drinks. Alcohol tolerance refers to the amount of alcohol you must drink to achieve desired effects. They will help outweigh the risk factors so you can experience a better life. If you identify with any factors, you can take steps to change them so that they no longer put you at what is post-acute withdrawal syndrome paws risk for an AUD.
Certain genetic factors may amplify the effects of environmental risk factors, increasing the likelihood of developing alcohol addiction. By unraveling the intricate interplay between genetics and environmental factors, researchers and healthcare professionals can gain a deeper understanding of the underlying mechanisms involved in alcohol addiction. In this section, we will explore the role of genetic factors in alcohol addiction, including genetic predisposition, specific genes and variants, and the interplay between genetics and environmental influences. The study methods used to identify genes that affect the risk for alcohol dependence assume that the presence of certain alleles increases the risk of alcoholism.
Starting in the late 1940s, researchers in Chile bred rats that preferred to drink alcohol-containing solutions as well as rats that avoided alcohol (Mardones and Segovia-Riquelme 1983). Finally, a GWAS in a sample of twins and their families recruited in Australia is currently being analyzed. Although none of the detected associations met genome-wide criteria for statistical significance, there was some evidence to support the previously reported association in GABRA2 as well as in a gene called ERAP1, which encodes the enzyme endoplasmic reticulum aminopeptidase 1 (Bierut et al. 2010). Another recent report (Bierut et al. 2010) described a GWAS using an overlapping set of COGA subjects as well as additional subjects recruited as part of other addiction research projects. Recently, COGA reported results of a GWAS that included 847 alcohol-dependent case and 552 control subjects (Edenberg et al. 2010). Thus, the analyses require very large samples because most variations only have small effects; moreover, the multiple testing involved in a GWAS reduces the statistical power to detect associations.
Family members serve as role models, and their behaviors around alcohol can shape how you view drinking. This is because adults born with FASDs tend to have psychiatric and personality disorders that increase their likelihood of abusing alcohol and drugs. Individuals with the alcohol-protective alleles also reported totally unexpected differences, such as more malaria, more myopia and several cancers, particularly more skin cancer and lung cancer, and more migraine with aura. They data-mined the analyses of DNA from saliva samples submitted by consenting 23andMe research participants, as well as the responses to the surveys of health and behavior available from the 23andMe database, and found a constellation of associations, not necessarily connected with alcohol.
Age of initiation of regular drinking (Initiation) was the age at which participants reported first drinking regularly, defined as once a month for 6 months or more. The Institutional Review Boards at all data gathering sites approved this study, and written consent was obtained from all participants. Probands (i.e., index individuals) were identified through alcohol treatment programs at seven U.S. sites. Parental divorce and relationship discord were examined separately in view of prior evidence that both parental marital status and the tenor of their relationship represent separate and unique influences on children’s outcomes27. Moreover, it is well recognized that many offspring are exposed to parental relationship discord even in Chelsea House Review the absence of parental divorce7–10. Parental divorce is common5, and 28.24% of American adults experience parental divorce or permanent non-marital parental separation prior to age 186.
Studies have reported an association of SNPs in CHRNA5–CHRNA3 (Wang et al. 2009) and CHRNA6–CHRNB3 (Hoft et al. 2009) gene clusters with alcohol dependence or alcohol consumption. The association of several noncoding ADH polymorphisms with alcohol dependence has been replicated in other studies (Edenberg 2007; Macgregor et al. 2009). These analyses detected significant evidence of association of alcoholism with 12 SNPs located in and around the ADH4 gene (Edenberg et al. 2006) and modest evidence of association with noncoding SNPs5 in ADH1A and ADH1B. These analyses detected linkage of alcoholism to a broad region on chromosome 4q that included the ADH gene cluster (Long et al. 1998; Prescott et al. 2006; Reich 1996; Reich et al. 1998; Williams et al. 1999). The influence of ADH variations on risk was further investigated through linkage studies performed in non-Asian families. Certain alleles in the ALDH2 gene, which encodes a key ALDH enzyme, can result in very low activity of the enzyme (denoted by the black arrow with a red line through it), again causing acetaldehyde accumulation and the resulting aversive effects.
