Drug addiction is a complex and intensely personal phenomenon. It affects the body and the mind, causing physical damage and psychological pain. The causes of addiction are equally complex, and the natural question becomes whether nature or nurture is responsible for a person’s drug abuse. The short answer is that it’s both. And it’s important to understand how factors from each realm come together to shape an addiction.

The physiology of addiction is clear. The structure of our brains and bodies makes us susceptible to the effects of substances, and when those substances have physically addictive properties, they often create a dependence that leads to addiction. The research and discussion of brain chemistry often focuses on one main culprit: dopamine, the brain’s main regulator of our reward circuit. Dopamine regulates functions such as emotion and the experience of pleasure, which is triggered by activities such as eating and sex. Drugs mimic that gratification and generate a positive reinforcement that leads to a desire and expectation for more. That extraordinarily great feeling — which humans are wired to crave — can be far more powerful than the conscious awareness that drugs are dangerous. That is why addictions can form around a number of substances and activities, from food and alcohol to sex and gambling. Dopamine is a powerful force.

But addiction is more complex than mere biology. Most people turn to drugs for psychological and emotional reasons. These are unique to each individual and manifest themselves differently in each case, but common reasons for drug use include a desire to suppress unwanted feelings, a history of emotional pain and torment, a struggle with depression and anguish, and feelings of self-loathing or fear. These can become overwhelming and drive a person to self-medicate. Other social and psychological experiences can also contribute to drug use: Rejection by loved ones; struggles at school or work; guilt or regret about past decisions and missed opportunities; or sexual, physical and mental abuse can easily pull someone into an addiction.

Circumstantial conditions also contribute to substance abuse. Bearing witness to horrific atrocities can push people to suppress memories or painful emotions using drugs. Growing up in fear or insecurity, being exposed to addiction from a young age, or growing up in unstable environments are also powerful experiences that can lead a person to engage in self-destructive activities. The sense of being perpetually medicated often masks the pain of the torment caused by these life conditions. These in turn interact with the biological mechanisms of addiction, creating a dependence that is reinforced by both body and mind.

So the most pressing question about addiction is not whether nature or nurture plays a role, but which factors from either nature or nurture are at work. Only then can an addict, health professional or loved one begin to dissect the underlying causes of substance abuse. And that is the objective of recovery: to identify the dynamics of the addiction, address the root causes, and chart a path to recovery. That process depends on a full understanding of both nature and nurture as they apply to the particular individual.