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Genetic Testing for Addiction Risk: Are These Tools Reliable?

A new genome-wide association study (GWAS) revealed that certain genetic factors drive some individuals to drink alcohol.

The study, led by Dr. Andrew Thompson, senior research associate at the University of Liverpool, targeted genes involved in alcohol use and addiction. The research showed that genes influence the risk of high alcohol consumption, and in turn, can lead to several diseases (more than 60) such as lung cancer (Thompson, A. et al., 2020). Advances in genetic testing, such as the GWAS study, offer valuable insight into how specific gene variations increase the risk of substance use disorders (SUD).

However, even with all the breakthroughs in genetic research, the validity of specific DNA assessment tools used to evaluate addiction risk is still heavily debated in scientific circles. In this article, we examine how genes can affect the risk of SUD, as well as the reliability and controversy surrounding current genetic testing tools used in predicting addiction. Finally, we discuss how DNA testing has its place in the addiction space, but should not replace a comprehensive individualized SUD assessment.

How Genes Affect Your Risk of Substance Use Disorder

Research suggests that 50% of addiction risk is genetic. Yet, making significant strides in identifying the exact genes and variants is still on-going. For example, we now know that the A1 allele of the dopamine receptor gene DRD2 occurs more often in people with alcohol or cocaine addiction (Blum, K. et al. 1990). We also know there are at least ten genetic variations that are confidently associated with a higher risk of SUD. The majority of these variations are involved with dopamine-related pathways (Blum, K. et al., 2018).

As addiction runs in families by way of genes, researchers often compare DNA sequences of family members to identify genes involved in substance use disorders. Now researchers are taking this search a step further by trying to establish accurate DNA assessment tests/tools to identify a person’s potential risk of addiction.

Genetic Testing Tools for Assessing Addiction Risk

Many companies have entered the genetic testing arena in the addiction space, claiming personalized care. Unfortunately, scientists have a healthy amount of skepticism concerning these tools. Many believe that companies have not done their due diligence before bringing these tests to market.

However, one researcher, Kenneth Blum (whose research led to finding the A1 allele of the dopamine receptor gene DRD2), spent over 30 years developing the Genetic Addiction Risk Score (GARS) test. GARS is a general risk assessment test of substance use disorders and non-substance craving behaviors. This test and LifeKit Predict, an opioid-specific risk assessment test, have been met with some promise in terms of clinical research. Both tools are considered “Direct to Consumer (DTC)” genetic tests, but GARS is the only patented genetic test on the market.

So, how does each product work? And what does the scientific community think of these DTC tests? We look at both questions below.

 

Genetic Addiction Risk Score (GARS) by Geneus 

How does it work? The interaction of neurotransmitters and genes that control the release of dopamine is called the Brain Reward Cascade (BRC). Variations within the BRC may predispose individuals to addictive behaviors and altered pain tolerance. From a quick cheek swab, the GARS test is believed to identify an individual’s vulnerability toward addiction, impulsive behaviors, and personality disorders, also defined as Reward Deficiency Syndrome (RDS) (Blum, K. et al., 2018). Within a week, the GARS report is sent to the individual with results.

LifeKit Predict by Prescient

How does it work? A DNA sample is collected from a cheek swab and sent to Prescient. They then analyze an individual’s 16 alleles involved in the brain reward pathway and compare them to individuals with and without addiction. Once analyzed, the test predicts (within 48 hours) a person’s risk of opioid dependence.

Are These Tests Reliable? What the Scientific Community Says

The answer to this question depends on who you ask. According to some research, the GARS test is believed to improve clinical interactions and decision-making (Blum, K. et al., 2018). Even with Blum’s vast experience and research, he holds stake in the company – some view this as a conflict of interest. And Prescient claims their test has 88% specificity that someone may have a risk for opioid dependency and 97% sensitivity that a person may not have increased genetic risk for opioid dependence. However, some in the scientific community have doubts about these statistics and the use of genetic tests in general, including:

  • GenomeWeb reported that Yale University professor Joel Gelertner, an expert in genetics and addiction, was skeptical that LifeKit’s predictive power would hold up when applied to larger datasets, and argued that without better validation, physicians should not use this type of testing (Ashford, M., 2017).
  • According to SciPol (Duke Initiative for Science & Society), Michael Vanyukov, a University of Pittsburgh professor of pharmaceutical sciences, psychiatry, and human genetics, states, “It’s hard to conceive of a genetic test or score that would be valuable as a predictor of opiate abuse or addiction in general. Heredity plays a relatively small role in determining variation in addiction risk, while choices and perceptions can play a big role. The error of a genetic score is likely to be great, and reliance on it in practice may be dangerous (SciPol, January 2020).”
  • A new article from the National Institutes of Health (NIH) states that genetic testing can provide only limited information about an inherited condition, it can’t predict symptom severity or progression, (NIH, 2020).

Additionally, many experts feel these DTC genetic addiction tests also have the potential for:

  • high false-positive rates
  • little to no professional addiction counseling if the results show a risk to substance use disorders
  • causing stress in an individual if they do not understand their results or report the findings to a clinician.

Why Comprehensive Assessments Matter

Predictive tests have their place in the addiction space, but are still in their infancy and need more development and published research. Addiction involves the interplay of environmental, cognitive, and biological factors, and genetic testing provides only partial information about a person’s risk for SUD. A comprehensive, individualized assessment with an addiction professional is still the most effective route to gauging one’s risk of developing a substance use disorder and effective treatment.

 

References:

Ashford, M. (2017, August 29). Prescient medicine launches addiction risk test developed with autogenomics. Retrieved from https://www.genomeweb.com/microarrays-multiplexing/prescient-medicine-launches-addiction-risk-test-developed-autogenomics#.XkbmxRNKjVp

Blum, K. et al. (1990). Allelic association of human dopamine D2 receptor gene in alcoholism. JAMA. 263(15): 2055-60.

Blum, K. et al. (2018). The Benefits of Genetic Addiction Risk Score (GARS) Testing in Substance Use Disorder (SUD). Int J Genom Data Min. 1: 115.

SciPol, n.a. (2020, January). Genetic test to predict opioid risk lacks proof, experts say. Retrieved from https://scipol.org/news/genetic-test-predict-opioid-risk-lacks-proof-experts-say

The National Institutes of Health (NIH), n.a. (2020). What are the risks and limitations of genetic testing? Retrieved from https://ghr.nlm.nih.gov/primer/testing/riskslimitations

Thompson, A. (2020). Functional validity, role, and implications of heavy alcohol consumption genetic loci. Science Advances. 6: 3.