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Can You Have Genetic Predispositions to Addiction?

By November 26, 2021 May 10th, 2022 No Comments

Substance Use Disorder is a serious problem in the United States. It affects millions of Americans every year. There are many different factors that can play into the development of drug and alcohol abuse. But did you know that your genetics can have an impact on your susceptibility to addiction?1

In this article, we will be examining studies of genetic factors that can potentially play into the development of alcoholism and opioid addiction.

Genetic Studies on Alcohol Use Disorder

For many people, alcohol addiction could be considered to be a complex genetic disease. Numerous studies have heavily suggested that alcoholism runs in families.2 But that doesn’t mean that genetics play a role in a person’s susceptibility to alcoholism. It simply means that if a person has realtives that have a history of alcoholism, there is a greater inferred likelyhood that the person may develop an alcohol use disorder.

Several twin studies in the US and Europe suggest that approximately 45-65% of the liability is due to genetic factors.3

In addition, genetic predisposition for alcoholism is demonstrated in animal studies. Mice and rats have been selectively bred for various genetic traits associated with alcohol dependence, including alcohol preference, alcohol sensitivity, and withdrawal sensitivity.4

Genetics Factors That Can Correlate with Alcohol Use Disorder

ADH (Alcohol Dehydrogenase) And Alcohol Metabolism

Several studies show that people who have at least one variant in the ADH gene are less likely to drink as much and more likely to be alcohol-free.5 Therefore, someone who drinks while having this genetic factor faces significantly less risk for alcohol-related problems. 

Recent research suggests that the human body has a genetically programmed aversion to alcohol. This aversion is called the “Alcohol Metabolic Disinhibition Response” (AMDR for short).6 When you drink alcohol, your body produces more acetaldehyde than it normally would. The extra acetaldehyde then causes an unpleasant reaction in your body. This trait is very common worldwide. As a result, people with extra acetaldehyde are less likely to become drunk, which means they can continue to drink without getting drunk.

What researchers have discovered about ADH by studying people who have alcoholism in their family history. Results show that the ADH gene has a stronger effect when it comes to influencing the chances of developing alcoholism when other genes also play a role.7 This explains why there are some people who are genetically more vulnerable to alcoholism and why other people seem to be less susceptible. It is also one of the reasons some people who have a biological predisposition to alcoholism may not actually become addicted in their lifetime.

GABRA2

GABRA2 is the gene responsible for producing the inhibitory neurotransmitter γ-Amino Butyric Acid, or GABA. When this gene is mutated, altered, or damaged, the brain is flooded with GABA, which exacerbates feelings of euphoria.8 It was observed that the presence of the GABRA2 gene was more closely associated with alcohol dependence and appeared at least in part to underlie the observed linkage.

Other findings regarding the GABRA2 gene came to the following conclusions:9

  • Early onset alcoholism was associated with increased risk of anxiety disorder and drug dependence.
  • Late onset alcoholism was associated with increased risk of depression and suicide attempts.
  • Comorbid drug dependence was associated with an increased risk of alcohol abuse and dependence.

This finding overlaps with previous studies reporting a relationship between this gene and alcoholism. GABRA2 appears to make some people more vulnerable to alcoholism than others. This means that for some, a drink or two might turn into a severe addiction. Others, with a different genetic makeup, are less likely to become addicted even if they binge drink frequently. However, there are also several factors in the GABRA2 gene that are linked to impulsive behavior. One of these, in particular, seems to be linked to less activity in the insula, which is an area of the brain associated with delay discounting (which is responsible for how quickly the euphoric effects of a substance take place).

CHRM2

Researchers believe that this gene may contribute to the development of alcohol addiction in certain people. This conclusion was supported by the finding that CHRM2 is significantly more common in alcoholic men than in the control group (a baseline of individuals who did not have the genetic factor).10 Other studies have confirmed this finding. In fact, these neural differences are strongest in those who started using substances at an early age or who have comorbid drug dependence. An electrophysiological (EEG) or neurological endophenotype is an inherited trait that appears to be expressed not as a physical characteristic, but rather as a biological sign that reveals the presence of a more permanent underlying psychological or neurological condition.

Other Considerations

It should be strongly noted that although genetics does affect whether or not someone becomes an alcoholic, there is no “genetic mark” that determines if someone will develop alcoholism in their lifetime. 

People with alcohol use disorder often have a genetic predisposition toward developing the disease, but the presence or absence of the condition may be affected by environmental factors, such as the social environment that person grows up in. Another challenge in the search for genetic variants that affect the risk for alcoholism is that there is extensive clinical diversity among those who meet criteria for the disorder. An alcoholic does not have to be a chronic heavy drinker to develop a problem. Even if someone only has one or two drinks a day over a prolonged period of time, they can become dependent on alcohol and suffer from problems related to its use.

Studies on Genetic Risk Factors for Opioid Addiction

Several studies in families with twins (individuals with very similar genetics but unique social upbringing) have shown that genetics can play a significant role in determining whether or not a person becomes dependent.11

A study of twins reared apart who were discordant for abuse of one or more drugs revealed that additive genetic influences were significantly correlated with lifetime drug use in both individuals.12

The research team behind these studies discovered that there were different factors influencing different people when it came to the development of opioid use disorders. The different factors influencing each individual were based on their unique genetic make-up and their early life experiences. The studies found evidence that the genetic influence on the trajectory of heroin use is quite small, with no more than 15% of the total variance in this transition being explained by genetic factors.12

This may be due to the fact that most of the subjects were male and only a few of them reported using heroin during their lifetime. Contrary to popular belief, not all drug use leads to addiction. Some drugs are abused by people who use them occasionally, and never become addicted. Other drugs are abused by people who use them occasionally and become addicted. Other people abuse drugs frequently, and never become addicted. For example, someone who uses heroin only once or twice and doesn’t get hooked is using a relatively low dose of the drug.

This implies a presence of genetic factors that can play into the development of opioid addiction. 

Dopamine Receptors and Genetics in Addiction

One genetic factor that can play into addiction is your dopamine receptors. Dopamine is a neurotransmitter that is widely distributed throughout the central nervous system. It is responsible for regulating movement, thinking, and feelings. There are many types of sensory receptors in the body, and they are involved with almost every aspect of human experience. In fact, they are involved with nearly every aspect of your daily life.

Within the scope of substance abuse, dopamine is the “pleasure chemical” and is produced in certain areas of the brain. It plays an important role in controlling impulsive behavior and promoting satisfaction.

As a result, the dopamine receptor genes are now being studied for their possible role in the development of addiction vulnerability. This has led to the discovery of several receptors which may play a role in opioid dependence vulnerability.13

Here are a few receptors that have been noted to have a correlation with opioid use disorders.

DRD2

The DRD2 gene codes for the D2 dopamine receptor which is a part of the dopaminergic (rewarding) pathway in the brain.14 A polymorphism in the DRD2 gene has been linked to drug abuse and addiction. This means people who have two or more of these polymorphisms are much more likely to become addicted to heroin.

OPRM1

This receptor is responsible for producing the protein that is essential for creating all feelings of euphoria. This gene is associated with creating physical dependence, and therefore individuals with certain variants of this gene have an increased risk for experiencing opioid withdrawal symptoms. A recent in-depth study has shown that a specific gene that affects this receptor is linked to opioid dependence.15

OPRD1

OPRD1 is a gene that codes for a protein that is found on the surface of cells in the brain, spinal cord, and gastrointestinal tract. It plays a part in the body’s response to pain and stress. Several studies have linked the association between variations in this gene and opioid addiction.16

Studies have compared the allele and genotype frequencies of people with heroin or alcohol dependence to those of a control group. However, none of the comparisons was statistically significant. This lack of evidence for a genetic contribution to addiction is not surprising given the highly polygenic nature of complex behaviors such as drug addiction.

OPRK1

The κ opioid receptor has been implicated in the regulation of stress responses, as well as countering the euphoric sensations produced by opioid agonists. The κ receptor is activated by endorphins and enkephalins. In a study regarding this receptor and opioid addiction, it was discovered that those with the A allele are less susceptible to the rewarding effects of opioids, and thus are at a reduced risk for developing opioid abuse.16

How Schick Shadel Can Help You Overcome Your Circumstance.

There are many different predispositions to developing drug and alcohol abuse and dependence. However, people with addiction need to have more than just their genetic history taken into account when entering treatment. They also need social and psychological help. Our team at Schick Shadel Hospital specializes in treating individuals with alcohol use disorders and opioid use disorders. 

Schick Shadel Hospital can help you get the personalized care you need. Our Aversion Therapy treatment helps reverse addiction by eliminating the brain’s craving for alcohol. Whether your addiction is reinforced by genetic, social, or other factors, our effective treatment helps to “retrain your brain” and stop addictive behaviors at the source. Give us just 10 days, and we’ll give you back your life!

Call us today at 1(800)CRAVING or visit our Contact Page.

References

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  2. Heath AC. Genetic influences on alcoholism risk: a review of adoption and twin studies. Alc Health Res World. 1995;19:166–171.
  3. Prescott CA, Kendler KS. Genetic and environmental contributions to alcohol abuse and dependence in a population-based sample of male twins. Am J Psychiatry. 1999;156:34–40.
  4. McBride WJ, Li TK. Animal models of alcoholism: neurobiology of high alcohol-drinking behavior in rodents. Crit Rev Neurobiol. 1998;12:339–69.
  5. Foroud T, Edenberg HJ, Crabbe JC. Genetic Research: Who Is At Risk for Alcoholism? Alcohol Research & Health. 2010;33:64–75.
  6. Hurley TD, Edenberg HJ. Genes encoding enzymes involved in ethanol metabolism. Alcohol Res. 2012;34:339–44.
  7. Higuchi S. Polymorphisms of ethanol metabolizing enzyme genes and alcoholism. Alcohol Alcohol Suppl. 1994;2:29–34.
  8. Edenberg HJ, et al. Variations in GABRA2, encoding the alpha 2 subunit of the GABA(A) receptor, are associated with alcohol dependence and with brain oscillations. Am J Hum Genet. 2004;74:705–14.
  9. Fehr C, et al. Confirmation of association of the GABRA2 gene with alcohol dependence by subtype-specific analysis. Psychiatr Genet. 2006;16:9–17.
  10. Luo X, et al. CHRM2 gene predisposes to alcohol dependence, drug dependence and affective disorders: results from an extended case-control structured association study. Hum Mol Genet. 2005;14:2421–34
  11. Mistry, C. J., Bawor, M., Desai, D., Marsh, D. C., & Samaan, Z. (2014). Genetics of Opioid Dependence: A Review of the Genetic Contribution to Opioid Dependence. Current psychiatry reviews, 10(2), 156–167. https://doi.org/10.2174/1573400510666140320000928
  12. Cadoret RJ, Troughton E, O’Gorman TW, Heywood E. An adoption study of genetic and environmental factors in drug abuse. Arch Gen Psychiatry. 1986;43:1131–6.
  13. Luquin-Piudo MR, Sanz P. Dopamine receptors. motor responses.and dopaminergic agonists. Neurologist . 2011; 17(6 ) Suppl 1 :S2–8.
  14. GeneCards Human Gene Database: DRD2 Gene. [cited: September 23]. Available from: http://www.genecards.org/cgi-bin/carddisp.pl?.gene=DRD2. 2011.
  15. Bond C, LaForge KS, Tian M, et al. Single-nucleotide polymorphism in the human mu opioid receptor gene alters beta-endorphin binding and activity: possible implications for opiate addiction. Proc Natl Acad Sci U S A 1998; 95(16): 9608-13. 68. Kapur S, Sharad S, Singh RA, Gupta AK. A118g polymorphism in mu opioid receptor gene (oprm1): association with opiate addiction in subjects of Indian origin. J Integr Neurosci 2007; 6(4): 511-22.
  16. Zhang H, Kranzler HR, Yang BZ, Luo X, Gelernter J. The OPRD1 and OPRK1 loci in alcohol or drug dependence: OPRD1 variation modulates substance dependence risk. Mol Psychiatry, 2008. 13(5): p. 531-43. 70. Franke, P., et al. Human delta-opioid receptor gene and susceptibility to heroin and alcohol dependence. Am J Med Genet, 1999. 88(5): 462-4. 71. Mayer P, Rochlitz H, Rauch E, et al. Association between a delta opioid receptor gene polymorphism and heroin dependence in man. Neuroreport 1997. 8(11): 2547-50.
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