Does Genetics Play a Role in Drug + Alcohol Addiction?

When someone you love struggles with substance use, one of the first questions you may ask is why. Did their environment influence them? Was it stress or trauma? Or could there be something deeper at play, something actually written in their DNA?

Today, research shows that addiction and genetics are, in fact, closely linked. But not in the direct way many people think.

Let’s explore this link and break down how genetics can both increase vulnerability to addiction and provide protective traits that reduce a person’s risk.

Addiction + Genetics: The Big Picture

The short answer is that while a person’s genetic makeup plays a key role in their risk of addiction, it doesn’t seal their fate.

Studies estimate that genes account for 40–60% of a person’s vulnerability to addiction. That means if addiction runs in your family, your chances of developing a substance use disorder are higher — but not guaranteed (Zhou, Polimanti & Kranzler, 2024).

Environmental factors — such as early exposure to drugs or alcohol, trauma, or chronic stress — also shape risk. The interaction between biology and environment creates a complex picture of addiction, with no single risk factor determining a person’s struggles (or lack thereof) with substances.

The Myth of an “Addiction Gene”

Despite popular belief, there isn’t a single “addiction gene.” Instead, multiple genes work together to influence how the brain responds to substances.

Recent genetic studies highlight dozens of variations linked to different types of addiction. For example, variations in the OPRM1 gene have been tied to opioid use disorder, while other genes affect risk for alcohol or stimulant addiction (Volkow & Muenke, National Institute on Drug Abuse, 2019).

This means addiction isn’t about one faulty gene — it’s about a genetic blueprint that interacts with a person’s environment and life experiences.

Addiction + Genetics: Key Risk Factors

If addiction is partly genetic, what does that mean in real life? People with genetic predispositions to addiction may:

• Experience stronger cravings or reward responses when using substances
• Have a harder time quitting once use begins
• Be more vulnerable to the negative effects of stress or trauma, triggering substance use as a coping mechanism

But remember: genetics may lay the foundation, but environment builds the house.
Even someone with a strong genetic risk can avoid addiction if they never drink or do drugs.

The genetics of alcohol use disorder

Research consistently shows that alcohol use disorder has a strong genetic component, though genes do not act alone. A meta-analysis of twin and adoption studies found that about 49% of the risk for AUD is due to genetic factors, with shared environment accounting for roughly 10% and the rest due to unique environmental influences (Verhulst, Neale & Kendler, 2015).

Another review places the heritability estimate for addictive behavior — including alcohol dependence — at about 50%, reinforcing that genetics make up roughly half of the risk profile for AUD (Friedel, Kaminski & Ripke, 2020).

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Can Genetics Protect You from Addiction?

Some people’s genes actually decrease their risk of developing a substance use disorder.

Certain versions of the ADH1B gene (like ADH1B2 or ADH1B3) break down alcohol so fast that it produces a surge of acetaldehyde, which causes unpleasant reactions like flushing and nausea. Another variant, ALDH2*2, slows the body’s ability to clear that acetaldehyde, making drinking even more uncomfortable. Together, these genetic differences can discourage heavy drinking and lower the risk of alcohol use disorder (Edenberg, Gelernter & Agrawal, 2019; Wall, Luczak & Hiller-Sturmhöfel, 2016; Mulligan et al., 2003).

But genes don’t work in isolation. Their protective power depends on how they interact with other genes, life circumstances, and the environment. One long-term study found that teens with protective ADH1B or ALDH2 alleles started drinking more slowly and steadily over time compared to peers without these alleles (Cleveland et al., 2018). Still, outside factors (like social norms, peer pressure, or easy access to alcohol) can either strengthen or weaken these protective effects (Wall, Luczak & Hiller-Sturmhöfel, 2016).

Why Understanding Addiction + Genetics Matters

Knowing that addiction has a genetic component can reduce stigma. Substance use disorder is not simply a matter of willpower — it’s a complex brain disease shaped by biology and environment.

This knowledge also allows researchers to:

• Empower families to recognize patterns and seek help early
• Develop personalized treatment plans tailored to genetic risk
• Expand preventive strategies for high-risk individuals

Understanding the genetic roots of addiction shows us it’s not about weakness or biology alone. It’s about a combination of factors that we can learn to navigate and overcome with the right support.

Getting Help for Addiction

Whether your family has a history of substance use or not, addiction is a treatable condition. Evidence-based therapies, medical support, and a compassionate, recovery-focused community environment can help individuals manage cravings, heal trauma, and reclaim their health and well-being.

At STR Behavioral Health, we provide detox, medication-assisted treatment, and residential programs designed to address all aspects of addiction.

Lasting recovery begins with that first step. Contact our admissions team today or complete the form below to learn more about our detox and addiction treatment programs. Recovery is possible — we’re here to help you.