Drug Addiction, Genes, and Your Environment

Medically Reviewed by Jennifer Casarella, MD on April 22, 2022
4 min read

Many things play into drug addiction, also known as substance use disorder. Why will some people become addicted to substances, while others won’t? There’s no single answer. Your likelihood for addiction depends on both your genes and your overall environment.

In order for you to develop an addiction, you first have to experiment with drugs. After repeated use of the drug, addiction becomes a possibility. From there on, your genetics are one thing that will determine how likely you are to actually become addicted.

Studies suggest that about half of a person’s risk of developing a drug addiction is based on their genetic makeup. This means that specific genes passed down in your family may put you at a higher risk for drug addiction.

But while genetics can play a large part in addiction, they’re not the only thing that leads to the condition. Your surroundings – your family, friends, lifestyle, and other things in your environment – can also put you at a higher risk for it.

To understand your risk for drug addiction, it’s important to look at these two factors together. Experts use epigenetics to explain substance abuse. This is the study of how parts of your environment can affect how your genetic code works.

Epigenetics explains why one identical twin may develop a drug addiction, while the other twin doesn’t. The two twins were born with the same genes. So, genetically, they have the same risk for drug addiction. But as they grow up, the twins may be around different influences. They’ll develop differently, and that will change their individual risk for addiction.

Through epigenetics, experts can understand how genetic factors and lifestyle choices affect someone’s risk for addiction.

One study looked at young people and their development of certain disorders. It found that drug use in people in early adolescence was strongly linked to things in the environment like family and social factors.

But as a person grew into young and middle adulthood, the use of certain drugs was tied more to genetics and less to family and social influences. As a person aged, the genetic risk of drug addiction went down slightly.

But it’s hard to understand whether a person’s drug addiction was caused by genetic factors or family influence if their parents also were addicted. To understand the genetic risk even more, experts looked at adopted children whose biological parents were addicted to drugs.

They found that adopted children had a higher risk of drug addiction if their biological parents were addicted. Experts also found that an adopted child’s risk of drug addiction was higher if their biological parent had alcoholism, criminal convictions, or a severe psychiatric illness.

This risk only grew if the child’s adoptive parents exposed them to further environmental disruptions, such as:

As you grow up, your surroundings will shape your behaviors. Things inside and outside of the household will affect you. You may be more likely to abuse drugs based on:

Access to drugs. Your ability to get drugs is important in the development of drug addictions. If you’re able to buy and use drugs easily, you’ll be more at risk for addiction.

Peer pressure. You may be more likely to abuse drugs if your peers sway you to do so. This is especially true for young people.

Level of family involvement. If you have a harsh family situation or weak bonds with your siblings and parents, you may be at a higher risk for addiction. In these cases, parents may not have as much oversight or control of their child’s actions. Because of this, they may do riskier things, like drug use.

Community involvement. Areas that have after-school activities tend to have less of a problem with drug addiction. Similarly, if people have access to exercise in their community, they’re less likely to engage in drug-related activities.

The time in your life that you begin drug use. If you begin to use drugs at an early age, it can change your brain development. This might heighten your chances of having a drug addiction.

Barriers to treatment. You may not have access to proper care for drug misuse. This could further impact your risk of addiction.

Disadvantaged neighborhoods. These areas may have limited access to things like adequate food and basic levels of safety. People in these areas are at risk for a lower quality of health. Research has shown that these disparities have a link to higher rates of substance misuse.

Your stress levels. Stress in your environment can trigger disorders such as drug addiction. In stressful situations, like the death of a loved one or another major life change, your body releases steroid hormones called glucocorticoids. This can lead to changes in systems throughout your body. One of these is your brain’s reward system.

When stress hormones interact with your reward system, you’re more likely to develop an addiction.

Experts believe that someday, they may be able to use a dopamine receptor, called D2, to tell if someone will become addicted to heroin, cocaine, or alcohol. Some brain imaging shows that people with fewer D2 receptors might be more likely to become addicted to drugs.

Your genes partly determine how many D2 receptors you have. But things in your environment can also influence this.

Researchers continue to learn about how your genes and environment interact to affect your risk of addiction. Through this research, they can help lessen the stigma of addiction, treat drug addiction faster, and create individual prevention and treatment plans for people with addictions.