Substance abuse and genetics are deeply intertwined, shaping how individuals respond to drugs and alcohol and influencing their risk of developing addiction. While environmental factors such as trauma, stress, and peer influences play a major role in substance abuse and addiction, research shows that genetic factors can significantly increase the risk of developing alcohol use disorders, opioid dependence, or other multiple substance use disorders. Addiction genetics highlights how a family’s history and shared genetics can affect the brain’s reward system, making certain people more vulnerable to addictive substances. Understanding the link between addiction hereditary factors and environmental influences offers valuable insight into why some individuals struggle with substance dependence while others do not—and why personalized treatment is essential.
Genetics and Substance Abuse
When the cycle of addiction occurs in a family, there is a 50% chance that children will be predisposed to addiction through genetics. Some substances carry a higher or lower genetic risk, but the average is one in two children risk addiction through genes alone.
According to NIDA’s Genetics Research Program, genes influence the following:
- The number and type of receptors in people’s brains
- How quickly a person’s body metabolizes a substance
- How the body responds to different substances
The development of most conditions, including substance use disorders, are linked to a variety of different genes which can impact a person’s risk level. With that said, scientists are constantly gathering more evidence to better understand the links between genes and substance use disorder. In doing so, treatments targeting gene risk factors may be future key to ending the cycle of addiction in families.
Gene risk factors that influence addiction include:
- Genes can affect how you respond to your environment, making certain people more susceptible to drug or alcohol misuse.
- Exposure to trauma and stress can “mark” or alter both gene expression and gene function, increasing a person’s risk for substance abuse later in life.
- Substance use while pregnant and breastfeeding can alter an infant’s genetic expression and function, resulting in a higher chance of developing an addiction.
- RNA viruses that affect dopamine receptors are frequently found in the genetic makeup of individuals with SUD and can be passed down to children, increasing the person’s vulnerability to addiction
- Genetic risk predictors, or genes “marked” by substance misuse can be passed down by a parent and can increase the probability of addiction.
Due to the complex relationship between genes and substance abuse, research supports the personalization of genetic testing to accurately define a person’s risk and vulnerability to addiction. As more evidence is discovered, there is more and more supporting data that says genetics may eventually be used in the treatment of substance abuse.
While these changes in gene expression can protect the child by lowering the severity of harm resulting from the parent’s addictive behaviors, they can also normalize, or desensitize, the child to the pattern of neglect and abuse. That being said, children with genetic markers for chronic alcoholism or addiction are not guaranteed — or “cursed” — to develop an addiction later in life. More often, the deciding factor that leads to alcoholism or drug abuse lies in epigenetics.
Epigenetics in the Cycle of Addiction in Families
Epigenetics is the study of genes in the context of environmental influences. Simply put, epigenetics is the relationship between a person’s genes and his or her environment.
General lifestyle factors that affect epigenetic patterns can include:
- Diet
- Obesity
- Physical activity
- Tobacco smoking
- Alcohol consumption
- Environmental pollutants
- Psychological stress
In the case of substance use disorders, epigenetic studies help to identify problematic lifestyle factors that may alter or “mark” a person’s genes and increase the likelihood of developing an addiction.
Adverse childhood experiences that affect epigenetic patterns include:
- Psychological abuse
- Physical abuse
- Sexual abuse
- Domestic abuse
- Exposure to substance abuse
- Exposure to mental illness
- Exposure to suicidal behaviors
- Exposure to criminal activity
There is a hand full of brain functions where epigenetic effects on a small number of genes are important, such as regulation of stress responsiveness and drug addiction. When children are exposed to abuse, their body often reacts by altering how new genes are produced.
How Can Your Environment Feed the Cycle of Addiction?
Your environment can feed the cycle of addiction. Environmental stressor can “mark” your DNA, so while your cells contain the same genetic information as when you were born, the body “keeps score” by shifting the creation of new cells in response to your environment.
In simple terms, when you fall off your bike and scrape your knee, your body produces new skin cells that are thicker—a scar—to protect that spot from future physical trauma. In the same way, the constant emotional trauma inflicted by a parent with a SUD will often trigger the creation of new “marked” cells in the child that attempt to minimize the impact of parental abuse.
Can Abuse Alter Your Genes?
When the body is exposed to trauma, it can be felt on a cellular level. When children grow up in an abusive home resulting from alcoholism or drug abuse, their cells can alter the process of creating new genes. The new genes are “marked” by a change in gene expression — a biological effect of PTSD.
A study examining the genes of individuals with PTSD highlights the significant impacts of childhood abuse and trauma, focusing on the alteration of an individual’s genes. Research findings report that people with a history of childhood trauma experience more genetic changes related to central nervous system development and immune system regulation. In contrast, those without a history of childhood abuse displayed genetic changes related to cell death and growth rate regulation.
In fact, research shows that people with PTSD and a history of childhood abuse have 12 times as many epigenetic marks, or changes to their gene expression. To clarify, people exposed to abuse during childhood suffer from a biologically different form of PTSD — the impacts of trauma having altered their genes since adolescence.
Studying DNA methylation, the cellular process of adding chemicals to genes to control their expression, can help researchers understand the relationship between genes and their impact on health and disease.
In 2014, the National Human Genome Research Institute alongside Johns Hopkins University began analyzing DNA methylation patterns across the entire genome, though their main focus is on brain regions that are important in schizophrenia, depression, and addiction. When complete, the new study will help paint a clearer picture of how variations in genetic composition can lead to a particular disease — namely, addiction.
Substance Abuse and Families
Children with one or more parents with a SUD experience higher rates of traumatic events including:
- Two or three times as likely to report childhood histories of emotional abuse, physical abuse, sexual abuse, and parental separation or divorce
- Two to five times as likely to have lived during childhood with household members who used illicit drugs had mental illnesses, attempted suicide, or participated in criminal behavior.
- Three to eight times as likely to have exposure to domestic violence against their mother.
Children living in families with alcohol-abusing parents are more likely than other children to have an unpredictable home life and to carry a burden of secrecy as a result of their attempts to hide the alcohol abuse from others (7,8).
These children also have an increased risk of a variety of other adverse childhood experiences, including being abused or neglected, witnessing domestic violence, and being exposed to drug-abusing, mentally ill, suicidal, or criminal household members (9,10,11,12,13,14,15,16,17,18,19,20).
Get Help for Addiction
Substance abuse and genetics are closely connected, with research showing that genetic factors and environmental influences both play a role in whether someone develops substance dependence. Studies on addiction genetics reveal a significant association between certain addiction genes, risk variants, and the risk of developing alcohol use disorders, opioid addictions, or cannabis use disorders. When combined with environmental factors like trauma or stress, these genetic influences can alter the brain’s reward system, making addictive substances more reinforcing and increasing the risk for addiction. Shared genetics are often seen in families with a history of substance abuse and addiction, where genes and environment work together to raise the likelihood of multiple substance use disorders. People with conditions such as anxiety disorder, bipolar disorder, or posttraumatic stress disorder may also have a higher addiction risk due to the complex interaction of addiction hereditary factors, the brain’s reward system, and exposure to drugs and alcohol.
If you or a loved one is struggling with symptoms and warning signs of drug and alcohol addiction—whether from alcohol addiction, opioid use disorders, or multiple substances—know that help is available. Our addiction center understands the connection between addiction risk, genes and environment, and the challenges of substance abuse and addiction. Don’t let opioid dependence, alcohol use disorders, or other addictive struggles control your life. Reach out today to begin treatment for abuse and addiction and break free from multiple substance use disorders with expert care and support.