What Really Causes Addiction? A Science-Based Look at Why People Get Hooked

Addiction affects millions of people around the world, yet it’s often misunderstood. For a long time, people believed addiction was simply about weak willpower or bad choices. But today, science tells a much deeper story—one that includes biology, psychology, trauma, and even the environment someone grows up in.

Let’s explore what really causes addiction, using real research, but in a way that’s easy to understand.

Addiction and the Brain: Why Drugs Feel So Good (and So Necessary)

When someone uses drugs or alcohol, their brain releases dopamine—a chemical linked to pleasure and reward. This happens in an area of the brain called the reward system, especially in the nucleus accumbens (Koob & Volkow, 2016). Over time, the brain starts to rely on that substance to feel good—or even just to feel normal.

Eventually, people don’t get the same high. This is called tolerance. At the same time, they may feel horrible without the drug (withdrawal), which makes quitting really hard.

Research also shows that drugs can change the prefrontal cortex—the part of the brain responsible for decision-making and self-control (Volkow et al., 2019). This is one reason people with addiction often make choices they wouldn’t otherwise make.

Mental Health and Addiction: A Difficult Combo

Many people who struggle with addiction also deal with mental health issues like depression, anxiety, PTSD, or ADHD. In fact, studies show that mental illness and addiction often go hand-in-hand (Grant et al., 2015).

Some people use substances to cope with emotional pain. This is known as the self-medication hypothesis (Khantzian, 1997). For example, someone with anxiety might drink alcohol to feel calm. Someone with trauma may use opioids to numb emotional pain. While it might help short-term, over time it usually makes things worse.

Are Some People Born More at Risk?

Yes—genetics play a role. If you have family members who struggle with addiction, you might have a higher risk too. Studies show that genes account for about 40–60% of a person’s risk (Goldman et al., 2005).

But genes aren’t destiny. Your environment and choices still matter. What you’re exposed to growing up plays a huge role.

Childhood, Trauma, and the Environment

Many people with addiction report having tough childhoods—homes where there was violence, abuse, neglect, or drug use. These early experiences, known as Adverse Childhood Experiences (ACEs), can raise the risk of addiction later in life (Felitti et al., 1998).

When kids grow up in constant stress, it changes how their brain and body react to the world. They may be more sensitive to stress and more likely to look for relief in drugs or alcohol.

Other environmental factors include:

• Poverty

• Homelessness

• Peer pressure

• Lack of access to healthcare or support

Addiction Is a Chronic Condition, Not a Failure

Experts now agree that addiction is a chronic, relapsing condition—more like diabetes or asthma than a simple bad habit (McLellan et al., 2000). That means it often takes long-term care, support, and patience.

Relapse doesn’t mean someone failed. It just means the person needs continued or adjusted treatment. Addiction recovery is rarely a straight line.

What Really Helps? Treatment and Hope

Addiction can be treated, and recovery is possible. The best treatment plans usually combine:

• Medication (like methadone or buprenorphine for opioid addiction)

• Therapy (like cognitive-behavioral therapy or trauma-informed counseling)

• Support networks (like 12-step programs or peer recovery groups)

• Harm reduction (like clean needle programs or overdose prevention)

It’s also important to treat any mental health conditions at the same time, so the root causes aren’t ignored.

Final Thoughts: Addiction Is Human

Addiction doesn’t make someone a bad person. It often means they’re in pain and trying to survive in the only way they know how. The more we understand addiction as a complex condition with biological, psychological, and social roots, the better we can help people heal—not just from drug use, but from the pain that came before it.

Sources

• Koob, G. F., & Volkow, N. D. (2016). Neurobiology of addiction: a neurocircuitry analysis. The Lancet Psychiatry, 3(8), 760–773.

• Volkow, N. D., et al. (2019). The neuroscience of drug reward and addiction. Physiology Reviews, 99(4), 2115–2140.

• Grant, B. F., et al. (2015). Epidemiology of DSM-5 Drug Use Disorder. JAMA Psychiatry, 72(12), 1235–1245.

• Khantzian, E. J. (1997). The self-medication hypothesis of substance use disorders. Harvard Review of Psychiatry, 4(5), 231–244.

• Goldman, D., Oroszi, G., & Ducci, F. (2005). The genetics of addictions. Nature Reviews Genetics, 6(7), 521–532.

• Felitti, V. J., et al. (1998). Relationship of childhood abuse and household dysfunction to leading causes of death in adults. American Journal of Preventive Medicine, 14(4), 245–258.

• McLellan, A. T., et al. (2000). Drug dependence, a chronic medical illness: implications for treatment. JAMA, 284(13), 1689-1695