Is Addiction Genetic?

What Is The Connection Between Addiction And Genetics?

Genetics can predispose an individual to a vulnerability to addiction. The National Institute on Drug Abuse (NIDA) found that genetic factors account for approximately 40%–60% of the risk of developing an addiction.

Addiction is a multifactorial disorder, so environmental and other influences play a significant role. Still, it appears some genes can contribute to the risk of developing a substance use disorder (SUD).

Genetics Vs. Heredity: What’s The Difference?

Genes are the basic units of heredity. They are composed of DNA and carry the instructions for our traits. They are located on 46 chromosomes within our cells. Genes control protein production, which is essential for bodily functions and processes.

Heredity is the transmission of genetic information from one generation to the next. Offspring receive one copy of each gene from both parents, which shape their unique traits through the combination of inherited genes and environmental influences.

Are There Addiction Genes?

While there is no single “addiction gene,” several genes have been identified that contribute to the risk of developing a SUD. The following are genes that we presently know contribute to addiction:

• DRD2 (Dopamine Receptor D2): This gene codes for the dopamine D2 receptor, which plays a role in the brain’s reward system. Variations in this gene have been linked to increased impulsivity and addiction risk.
• OPRM1 (Mu-Opioid Receptor): This gene encodes the μ-opioid receptor, which is involved in the perception of pain and the effects of opioids. Certain variants of this gene may contribute to opioid addiction vulnerability.
• GABRA2 (Gamma-Aminobutyric Acid Type A Receptor Subunit Alpha2): Variations in this gene have been linked to alcohol dependence, impulsivity, and increased risk-taking behavior.
• SLC6A4 (Serotonin Transporter): This gene regulates the reuptake of serotonin, a neurotransmitter involved in mood regulation and addiction. Certain variants have been associated with increased vulnerability to SUDs.
• COMT (Catechol-O-Methyltransferase): This gene metabolizes dopamine and other neurotransmitters. Variations in the COMT gene have been linked to differences in drug reward sensitivity and addiction risk.

These genes contribute to individual risks but do not directly cause addiction.

This table lists nine genes with an identifiable connection to substance use. Note that the CYP2A6 gene is the only one with strong evidence linking it to the associated addiction.

Gene	Evidence	Associated Addiction	Other Associated Trait
CYP2A6	Strong	Nicotine addiction	Nicotine metabolism
ANKK1 (DRD2 Taq1A1)	Fair	Gambling disorder, gaming disorder	Dopamine D2 receptor density
CRHR1	Fair	Gaming addiction	Stress response
KCNG2	Fair	Opioid dependence	–
NCAM1	Fair	Cannabis use	Neurodevelopment, cognition
CADM2	Fair	Cannabis use, alcohol consumption	Synaptic cell adhesion
ADH1B	Fair	Alcoholism	Alcohol metabolism
ALDH2	Fair	Alcoholism	Alcohol metabolism
GABRA2	Fair	Alcoholism	Regulate brain activity

Factors That Influence Addiction

Both genetic and learned personality traits can be damaging if they lead to addictive behaviors. Understanding genetics and one’s environment is crucial for developing effective prevention and treatment strategies.

Genetic Factors

While there is no single “addiction gene,” the table above identifies several genes that may contribute to the risk of developing SUDs, which then control biochemical reactions that lead to emotions, feelings, and actions. For example:

• Dopamine regulation: Dopamine is a neurotransmitter that plays an important role in the brain’s reward system. Alterations in dopamine regulation can increase the risk of addiction.
• GABA (gamma-aminobutyric acid) regulation: GABA is an inhibitory neurotransmitter that helps regulate brain activity, and imbalances in GABA signaling have been linked to addiction.
• Emotional regulation: Genes involved in the body’s emotional regulation can influence an individual’s vulnerability to addiction.

Environmental Factors

Environmental factors play a significant role in the development of addiction. These include:

Peer Pressure And Social Influences

Peer pressure, social norms, and cultural attitudes toward substance use can shape an individual’s behavior and increase the risk of addiction.

Exposure To Trauma

Traumatic experiences, such as abuse, neglect, or exposure to violence, can increase the likelihood of developing SUDs as a coping mechanism.

Availability And Accessibility Of Substances

Although age restrictions and other preventative measures are in place, substances remain readily available in both rural and urban environments.

Socioeconomic Status

Poverty, lack of education, and poor living conditions can contribute to increased stress, as does limited access to resources, which can increase the risk of addiction. However, substance abuse is seen throughout all economic levels.

How Do Genes And Environment Affect Each Other?

The gene-environment interplay refers to how genetic factors and environmental exposures influence the risk of developing a particular trait or condition, including addiction. This interaction can occur in several ways:

• Environmental factors can modify gene expression: Certain environmental exposures, such as stress, trauma, or substance use, can trigger epigenetic changes that alter the expression of genes involved in addiction pathways. These epigenetic modifications can increase or decrease an individual’s susceptibility to substance abuse.
• Genes can influence an individual’s response to environmental factors: An individual’s genetic makeup can influence how they perceive and respond to environmental stimuli, including stress, peer pressure, and exposure to addictive substances. For example, individuals with specific genetic variations may be more sensitive to the rewarding effects of drugs or alcohol, increasing their risk of developing addiction.
• Gene-environment correlation: This phenomenon occurs when an individual’s genotype influences their exposure to certain environments or experiences. For instance, individuals with genetic variations associated with impulsivity or sensation-seeking may be more likely to seek out environments or situations that increase their exposure to addictive substances.

Other Factors That Contribute To Drug Abuse And Addiction

There are other factors outside of genetics that can contribute to a heightened risk of developing an addiction, including:

• Mental health disorders: Those with depression, anxiety, or post-traumatic stress disorder (PTSD) are at a higher risk of developing SUDs as a form of self-medication.
• Personality traits: Impulsivity and risk-taking behavior are linked to an increased vulnerability to addiction.
• Early exposure: Individuals who start using drugs or alcohol at a young age are more likely to develop addiction later in life.
• Lack of social support or coping mechanisms: Inadequate social support systems and ineffective coping strategies can increase the risk of turning to substance use as a means of dealing with stress or emotional challenges.

The Role Of Family History

Individuals with a first-degree relative (parent or sibling) with a contributing gene have a two to four times greater chance of developing a substance abuse problem. However, just because you have a gene or a specific set of genes does not mean you will abuse substances or become addicted.  Studies show that about half of people who abuse drugs do not have the preexisting genes.

Even if you do have the gene, your environment is almost always going to be the determining factor as to whether you will abuse drugs or become addicted.

The following familial factors can influence addiction risk:

• Genetic transmission: Genetic variations can be passed down from parents to their children.
• Epigenetic factors: Environmental influences can cause epigenetic changes (modifications that affect gene expression without altering the DNA sequence) that can be passed down through generations.
• Shared environment: Family members often share similar environments and are exposed to the same risk factors for addiction, such as stress, trauma, shame, humiliation, and exposure to substances.
• Learned behaviors: Addictive behaviors and attitudes toward substance use can be learned and reinforced within families.

How Family Influences Teen Drug Use

Family dynamics influence the likelihood of substance abuse, which usually manifests itself in the teenage years, although it is increasingly seen in younger children.

According to a study by the Substance Abuse and Mental Health Services Administration (SAMHSA), teenagers living in households with high levels of conflict and poor communication are more likely to engage in drug use. Children learn from their environment, and today, there are many influences outside the family. However, parental attitudes and behaviors toward substance use can and do have a great effect on a child’s perception.

Can You Test Your Genes For Addiction Risk?

Testing for addiction risk through gene identification is a new field, and such testing has to be approached with caution. The methods that are now available for testing are:

• Genotyping: This involves analyzing specific genetic variants or mutations associated with addiction risk.
• Whole-genome sequencing: This approach involves sequencing an individual’s entire genome to identify genetic variations that may contribute to addiction risk.
• Epigenetic analysis: In addition to genetic variations, epigenetic modifications (e.g., DNA methylation and histone modifications) can influence gene expression and contribute to addiction risk. Epigenetic analysis can provide insights into how environmental factors interact with an individual’s genetic makeup.

It’s important to note that genetic testing for addiction is still in its early stages, and the interpretation of results is complex. Genetic testing should be accompanied by genetic counseling to ensure that individuals understand the limitations and implications of the results.

Ethical Considerations In Genetic Testing For Addiction

As genetic testing for addiction becomes more prevalent, it is important to address the ethical considerations surrounding this practice. Some of the key ethical issues include:

• Privacy and confidentiality: Genetic information is highly sensitive and measures must be taken to protect the privacy and confidentiality of individuals undergoing genetic testing.
• Informed consent: Individuals must be fully informed about the potential benefits, risks, and limitations of genetic testing for addiction and provide voluntary consent before undergoing any testing procedures.
• Discrimination and stigmatization: There is a risk that genetic information could be used to discriminate against individuals in employment, insurance, or other settings, leading to societal stigmatization and marginalization.
• Access and equity: Genetic testing and personalized medicine approaches may be expensive and inaccessible for some, raising concerns about equitable access to these services.
• Psychological impact: Learning about one’s genetic risk for addiction can have psychological implications, potentially leading to anxiety, depression, or feelings of determinism.

To address these ethical concerns, policies and guidelines must be developed to ensure the responsible and ethical use of genetic information in the context of addiction. This includes establishing privacy and data protection measures, implementing anti-discrimination laws, and providing appropriate genetic counseling and support services.

Ongoing public education is crucial to promote understanding and acceptance of genetic testing for addiction while addressing potential misconceptions.

Help Is Available

Whether you are genetically predisposed to addiction or not, if you or a loved one are struggling with substance abuse, help is available.

Regardless of the reason for your substance use, evidence-based treatments can help you recover and start living an addition-free life. Reach out to a treatment provider today to learn more.