Is Drug Addiction Genetic?

Genetics vs. Heredity: What’s the Difference?

The terms ‘genetics’ and ‘heredity’ are sometimes used interchangeably, but there are differences that are important to understand.

• Genetics refers to the study of genes or heredity.1,2 Genes are units of DNA that are passed down from parents and specify certain traits.1 Genes are housed on chromosomes. Humans have about 20,000 genes arranged on their chromosomes.3 People have 46 chromosomes in 23 pairs. Individuals inherit one of each pair from their mother and one of each pair from their father.4 This happens at random, which explains the differences between siblings. Individuals share about 50% of their genes with first-degree relatives, like parents, siblings, and children.5
• Heredity refers to the way that different characteristics and traits are passed down from parents to children through changes in genes and the DNA sequence.6 An inherited trait is genetically determined,7 but not all traits are strictly genetic. The expression of many genes is also influenced by the environment.7 However, heredity accounts for certain traits, such as height and eye color.1

What is the Link Between Heredity and Drug Addiction?

Since parents pass on certain genes to their children, certain diseases that are linked to genetics might “run” in the family.6 Changes in DNA and genes can affect the risk for certain diseases, but it’s complex, and DNA can even be “remodeled” by exposure to different environmental factors.1 Some diseases, like cystic fibrosis, occur due to mutations in a single gene.1 However, many other conditions, including addiction and other health complications, are thought to develop as a result of several potential genetic and environmental factors, as well as the interplay between these various influences.1

This means that even if you have a family history of addiction, you’re not necessarily guaranteed to develop an addiction. You need to have access to the drug, use it repeatedly, and be exposed to certain environmental influences to develop an addiction. In general, genes are thought to account for about half of a person’s risk of addiction.1

Environmental and Other Contributing Factors

Various interactions between an individual’s genes and the environment, including their upbringing—as well as other biological, social, and cognitive factors—can potentially increase someone’s overall risk of substance use and addiction.8 Some of these factors can include: 9-14

• Exposure to adverse early life experiences. Trauma, abuse, neglect, or witnessing domestic violence can negatively affect brain development and certain brain structures, impacting impulse control, decision-making abilities, emotional regulation, and social and emotional skills.
• Other family factors that influenced childhood experiences. Examples include parental substance use, poor role modeling, poor parental supervision, a lack of emotional warmth, or parental rejection.
• Environmental factors. Living in high-crime areas, starting substance use young, having low socioeconomic status, easy access to substances, permissive community norms, or being unemployed can increase the risk of substance use and addiction. Chronic exposure to such factors may alter the brain and certain behaviors, such as impulsivity and sensation-seeking, that could further increase the risk of addiction.
• Learned behaviors combined with brain changes. Pleasurable effects of substance use can reinforce repeated use. Repeated substance use may alter the brain’s reward circuit, leading to extreme stress when not taking the substance. These changes, combined with exposure to Pavlovian conditioned drug-related cues, can impact addiction. Pavlovian conditioned cues are triggers—such as seeing alcohol—that are linked with pleasurable experiences (such as being with friends), prompting behaviors that reinforce substance use.
• Inflammation/neuroinflammation. Some research evidence suggests that inflammatory processes may play a role in the development and course of substance use disorders and other mental health issues (which may one day offer novel treatment targets).21
• Psychiatric factors, some of which may have a genetic component. This can include mental health issues such as schizophrenia, major depression, and personality disorders, which are often associated with addiction.

Are There Addiction Genes?

There isn’t just one alcoholism or addiction gene.15 Scientists have identified multiple genes associated with addiction, in general, as well as genes associated with addiction to specific substances.16,17 Although research in this area is ongoing, some of the genes associated with addiction—and protection against addiction, too—include:1,16-18

• Alcohol dehydrogenase 1B (ADH1B) and aldehyde dehydrogenase 2 (ALDH2; mitochondrial aldehyde dehydrogenase). These genes play a role in the metabolism of alcohol. Genetic differences that lead to higher ADH1B activity or lower ALDH2 activity can result in uncomfortable symptoms when drinking alcohol; such variations in gene expression may have a protective effect against alcoholism.
• GABRA2 and CHRM2. These genes have been linked to alcohol use disorder (AUD)—a medical condition defined by the uncontrollable use of alcohol despite negative consequences. In addition, both of these genes appear to be strongly associated with early-onset alcoholism.
• MAOA, SLC6A4, COMT, and other genes associated with stress resilience. People with these genes may have individual differences that impact stress responses, which, when combined with other influences, could impact addiction.
• CHRNA2. Researchers have found that low levels of expression of this gene are associated with cannabis use disorder (marijuana addiction).
• CUL3, PDE4B, and PTGER3. A large study of an international database found more than 400 locations in the human genome and at least 566 variants in these locations that are related to smoking or alcohol use. CUL3, PDE4B, and PTGER3 were specifically identified as playing a significant role.
• HIST1H2BD. This was identified in one study as being associated with cocaine dependence.

How Are Genes Tested For Addiction Risk?

Specific genetic testing may one day help better identify individual susceptibility to addiction. Genetic testing can potentially help determine a person’s unique addiction risks, but it’s an area that requires more research.1

Challenges in Research

Numerous scientists have collected lots of data in this area, but varied software systems and measurement formats make it difficult for them to share data. The National Institutes of Health (NIH) created the Big Data to Knowledge (BD2K) program to help scientists use big data and data science in their research to glean more genetic information that might give disease insights.1

Pharmacogenetics is the emerging science that will help health care providers improve treatment by tailoring medications to an individual’s genetic makeup.1

Overcoming Addiction and Finding Treatment

Even if you have a genetic predisposition to addiction, you can take steps to manage your risk and minimize your chances of addiction. If you or someone you care about is struggling with addiction, you should know that treatment can help you start the path to recovery to overcome addiction.

How Treatment Helps

Treatment can help you understand addiction and your triggers, teach you ways to prevent relapse, and help you develop better stress management and coping skills so you can abstain from using drugs and alcohol. It should be individualized to your unique needs, which can include:19

• Physical and psychological health.
• Social, vocational, legal needs.
• Other personal circumstances.

First Steps of Recovery

The first step in recovery might be to enter detox so you can receive support while withdrawing from the substance. Detox can keep you safe and comfortable as your body detoxifies from the substance.19

You might then enter an inpatient rehab, where you live for the duration of treatment and receive round-the-clock care and support, or an outpatient rehab, where you live at home and travel to a facility for treatment. Inpatient and outpatient rehab can occur on a variety of levels of intensity and can last for different lengths of time, which can depend on your unique needs.20

Common Interventions and Therapies

Interventions and/or addiction therapies you may receive during treatment may include: 19,20

• Medication. Depending on the substance, you may receive medication to manage withdrawals, help avoid drug or alcohol use, and prevent relapse. The treatment center may use pharmacogenetic testing to find the best medications for you and minimize the risk of adverse effects.
• Behavioral therapies. This can include a wide range of therapies, such as cognitive-behavioral therapy (CBT), designed to help change thoughts and behaviors related to substance use; or motivational interviewing (MI), which can help people resolve any ambivalence toward their recovery needs and better engage with treatment efforts. Behavioral therapies are often provided in both individual and group therapy settings.
• Mutual support groups, such as Alcoholics Anonymous (AA) or Narcotics Anonymous (NA). You may benefit from ongoing support from others who are also in recovery.

Find Addiction Treatment Near You

Addiction can affect anyone, but recovery is possible. If you or a family member is ready to overcome addiction, we’re here to provide the support and resources you need. The experienced professionals at our nationwide network of treatment centers offer proven treatment methods, including individual counseling, group therapy, medication-assisted treatment. Call now for a confidential consultation and to learn more about our programs, success stories, and take the first step towards a healthier, happier life.