Substance Use Disorders (SUDs) are defined by compulsive and uncontrolled substance use, even with severe negative consequences. [1] SUDs are highly prevalent, leading to health issues, social problems, and public health challenges. [2][3] A new multi-ancestry research study has identified hundreds of genetic signals that influence SUD risk in individuals from Europe, Africa, and the Americas, which could be key to identifying and treating SUDs in these populations. [2]
Are substance use disorders really "genetic"?
Research has shown that there are hundreds of shared genes between individuals suffering from multiple different SUDs. [2] Those with a higher amount of these genes expressed had an increased chance of developing SUDs. [2] While other variables certainly play a part in substance use, such as environmental and socioeconomic factors, the data suggest there is also a key genetic component. [2]
What did the new multi-ancestry study find?
This new research was a large meta-analysis of genetic data, aiming to identify any genes linked to a greater risk of developing SUDs. [2] The samples used were genetically similar to those from the 1000 Genomes Project, specifically the European (1kg-EUR-like), African (1kg-AFR-like), and American mixed (1kg-AMR-like) populations. [2]
They identified 220 genetic loci (specific locations on a chromosome) associated with SUDs, including 40 new findings. [2] In total, researchers found 785 SUD-shared genes. [2] These genes are expressed in multiple regions of the brain, including the amygdala (which controls emotion responses) and hippocampus (responsible for memory as well as building connections between memory and emotion). [2]
Using this information, researchers were able to give each individual in the sample a ‘polygenic score’, which provides an estimate of the genetic risk of developing an SUD. [2] They advise that these polygenic scores could be used in the future to help identify those at higher risk of developing an SUD. [2]
220 genetic loci and 785 shared genes
This study found a total of 785 shared genes associated with SUDs spread across 220 specific genetic locations. [2] This high number of shared genes and loci provides ample opportunity to develop treatments targeting these specific genes and locations.
What do polygenic risk scores mean for people?
Polygenic risk scores can be used to calculate an individual's relative risk of developing a disease based on their genetics. [4] Thanks to the Human Genome Project, this data is available for a wide range of different conditions. While it can provide some useful information, there are several limitations. These include: [4]
- It provides a score for relative risk (i.e., in comparison to other people with a different genetic makeup), rather than an absolute risk (which is someone’s overall chances of developing a certain condition).
- It does not provide any information on the time frame or progression of the disease.
- It does not take into account any other risk factors for developing the disease.
Implications in treatment and prevention
Knowing which populations are at an increased risk of certain diseases can help individualize screening programs and treatments. Those with higher polygenic risk scores could be enrolled in a screening program to help prevent the development of SUDs.
It also opens the door for treatments targeting specific genes. In this latest research study, several drugs were identified that could target some of the SUD-shared genes, and therefore could be repurposed for treating SUDs. [2] As further knowledge of genes develops, treatment and prevention programs could become more and more targeted, providing a streamlined and effective program.
Genes, environment, and stigma
While genetic factors play a role in SUD risk, these genes do not work in isolation. Environmental factors, such as childhood trauma and socioeconomic conditions, can interact with the underlying genetic predisposition to influence whether an individual develops a SUD. This means that having genetic risk factors doesn't guarantee developing an SUD, and lacking them doesn't provide immunity from SUD.
Stigma is a huge issue with SUDs, impacting both provision and access to treatment. [5] There’s debate as to whether genetic explanations could increase or decrease the current stigma. In the event it does increase SUD stigma, it is important to take countermeasures to properly address this to minimize its impact on care access.
Could genetic explanations reduce or increase stigma?
Genetic research into substance use disorders (SUDs) could unintentionally contribute to new forms of stigma, with individuals viewed as “broken” or fundamentally flawed at a DNA level. People identified as having a higher genetic risk may face bias in employment, insurance, or social settings, potentially experiencing increased discrimination and social exclusion. At the same time, when communicated within a biopsychosocial framework, genetic findings can help reframe SUDs as medical conditions influenced by biological vulnerability, environmental factors, and lived experience. This perspective may reduce moral blame and promote more compassionate, evidence-based approaches to prevention, treatment, and recovery.
What this means if you have a family history of addiction
If you have family members who have struggled with SUDs, you may have an elevated genetic risk, but this doesn't mean you're guaranteed to develop an SUD yourself. By recognizing that you might be more vulnerable to SUDs, you can make active decisions to reduce your exposure to substances and reduce environmental factors. This includes building strong social connections, developing healthy coping mechanisms for stress, and maintaining good overall physical and mental health.
Getting help for substance use disorders
If you or someone you know is struggling with substance use, help is available. Start by reaching out to a medical or mental health professional who can help initiate and support your SUD treatment. Treatment options often include medical detox, behavioural therapies, and support groups. With appropriate support and treatment, people with SUDs can achieve long-term recovery and improved quality of life.
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