Addiction is a chronic, relapsing disease that involves abnormal reward circuits in the brain, driving substance use even with severe negative consequences. Like most diseases, addiction is caused by a combination of inherited (or genetic) and environmental (or social) factors. However, recent studies have found that genetic risks can make a person much more likely to develop a drug or alcohol addiction than previously believed.
- As much as 60% of the likelihood of an individual developing an addiction is based on their genetics. [1]
- Environmental, socio-economic, and behavioural factors also influence addiction development.
- Advances in technology, including genome-wide association studies (GWAS), have helped identify hundreds of specific genetic loci related to addiction.
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Understanding addiction and genetics
Recent research has helped to uncover the complex genetics involved in addiction.[2] Genome-wide association studies (GWAS) have helped identify links between specific genes and certain disorders.[2] These studies have discovered hundreds of shared genes between individuals suffering from addiction to multiple different substances, uncovering that genetics plays a bigger role in addiction than previously thought.[3][4] These account for up to 60% of the likelihood of developing addiction.[1]
However, these genes do not work in isolation. Epigenetics is the study of factors that influence gene activity and expression.[2] Environmental factors, such as childhood trauma and socioeconomic conditions, can affect whether certain genes are activated or not, therefore influencing whether an individual develops an addiction.[2] This means that having genetic risk factors doesn't guarantee the development of addiction, and lacking them doesn't provide immunity.
Heredity vs genetics
The terms ‘hereditary’ and ‘genetics’ are often used interchangeably, but there are important differences between the two. Hereditary, or ‘inherited’, refers to genes or traits that are passed down from parent to offspring.[5] Genetics is a broader term that relates to all genes, whether they are inherited or influenced by environment and behavioural factors.[6]
As such, everything hereditary is genetic, but not everything genetic is hereditary. Genetics is generally more useful when studying addiction as it encompasses all factors influencing gene activity and expression, not just those inherited from parents.
Current research into addiction and genetics
Multiple studies have found that substance abuse and addiction are genetic.[3][4][7] One recent study has uncovered hundreds of specific genetic loci that are associated with developing addiction.[4] Genetically predisposed individuals are more likely to form addiction pathways in their brains when exposed to substances or other triggering environmental factors.
Knowing the exact genes involved in addiction allows for more targeted treatments to be developed. One study identified several drugs that could target some of the addiction-related genes, and therefore could be repurposed for treating addiction.[4]
Screening programs could also be implemented for those identified as having a higher risk of developing addiction. For example, improved drug education and awareness programs for teens, including teaching refusal skills to help reduce peer pressure. As further knowledge of genes develops, treatment and prevention programs could become further targeted and effective.
Examples of addictive genes
Below are some examples of genes associated with addiction to different substances:
Genetic predisposition vs rewiring the brain
Pain and pleasure are primary motivators for human behavior, as well as most species in the animal kingdom. Humans are hardwired to avoid behaviors that cause pain and repeat behaviors that cause pleasure, which is closely linked to the formation of addiction pathways. Many of the pleasure-seeking activities and substances (food, sex, and drugs, and alcohol) are also believed to be addictive in nature, as they activate the dopamine pathways (aka addiction pathways) in the brain.[1][2][3]
This is part of our basic survival instinct and means that addiction, or the potential for it, is hardwired into our brains. The difference is that some people are more vulnerable to developing these pathways because of deficiencies in dopamine or other mood-related chemicals, or because of their genes, personality, or the way their brains are wired.
However, this does not mean everyone with a genetic predisposition for addiction is destined to develop a drug or alcohol problem. The risk factors for addiction are varied and include things like genes, personality traits, and even brain structure, but also individual choices, early exposure, and environmental factors.[2][3][4] Even those who do go on to develop addictions can overcome them, sometimes even without professional help.[4]
Also, the brain produces pleasure chemicals like dopamine and serotonin naturally in response to healthy behaviors like exercise, socializing, and even engaging in enjoyable activities. Substituting these healthy replacement behaviors is one positive way to help the brain recover from addiction and rewire the old addiction pathways in the brain.[4]
Addictive personality
The interplay between genetic predisposition and the individual is commonly mistaken for the vague term “addictive personality”. In actuality, addictive personalities are far more complex. While some personality traits can make a person more prone to developing an addiction, there is no hard science or evidence that one specific type of personality is linked to addiction. It is also true that preexisting co-occurring disorders such as bipolar disorder or anxiety disorders increase the likelihood of alcohol and drug abuse. Find out more about addictive personalities by reading our guide.
Testing for addictive genes
Currently, genetic testing for addiction risk is not routinely offered in clinical settings. Several companies offer direct-to-consumer genetic testing, often through either blood or saliva samples, which can provide some insight into addiction risk.[10] However, these have been associated with false-negative and false-positive results.[11]
Clinical genetic testing might be recommended in some cases, including individuals with a strong family history of addiction or those participating in research studies. Genetic testing results should be interpreted carefully and discussed with a healthcare professional. The presence of addiction-associated genes doesn't guarantee an individual will develop addiction, and the absence of them doesn't guarantee protection. These tests provide addiction risk estimates rather than definitive answers.
Are genetic risk factors the same for all substance addictions?
Genetic risk factors can vary significantly across different substances, although there is some overlap. As mentioned, several substance-specific genes exist, which affect how receptors in the brain respond to those specific substances. For example, the CHRNA5 gene specifically influences nicotine dependence risk, while the CHRNA2 gene is particularly associated with cannabis use disorder.[2][9]
However, some genes can impact multiple different substances, such as the DRD2 gene, which is associated with alcohol, cocaine, and opioid use disorders.[8] Addiction risk often comes from many genes working together rather than a single gene. Different combinations of genetic variants can create varying levels of risk for different substances, explaining why someone might be more vulnerable to one type of addiction than another.
Treatment
While the link between family history, genetics, and addiction is undeniable, it does not mean that there is no hope for those who have a drug or alcohol dependence. Research shows that about 60% of people who develop an addiction eventually stop using drugs and alcohol, proving that for most people, addiction is not an incurable or terminal disease.[4]
Both inpatient and outpatient treatment centers offer varied techniques that are designed to help people from all walks of life and have specific treatment types to help with genetic affiliation with addiction. These will often include cognitive therapies that can help identify the route of addictive tendencies and help to develop methodologies and coping mechanisms for controlling urges and triggers. Contact a treatment center today to start your journey to recovery.
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