What Science Says

Addiction is a disease that affects both the brain and behavior. Decades of research in neuroscience, behavioral science and brain imaging clearly show that addiction is a disorder of the reward center of the brain.

Addiction is not a moral failing. It is an illness that causes lasting changes in brain function that are hard to reverse. While initial use of alcohol or other drugs is a choice, repeated use can lead to profound changes that disturb the way nerve cells in the brain send, receive and process information. 

A Vulnerable Brain

Research points to structural and functional differences in the brain and to genetic factors that may predispose some individuals to this disease.

When a person does something that satisfies a need or fulfills a desire, dopamine is released in the brain and produces pleasure. It serves as a signal that the action promotes survival. The brain records this experience and we are likely to do it again.

In nature, rewards usually only come with effort and after a delay. But addictive substances shortcut this process and flood the brain with dopamine.

Loss of Control

In a person who is suffering from addiction, the natural reward circuits get hijacked, while the need to use the drug strongly persists.

The changes that occur include interfering with the brain’s natural chemical systems and over-stimulating the “reward pathway” of the brain. Once this happens, the substance activates the same circuits linked to survival, driving powerful urges no different from those driving the need to eat or drink water.  

When the disease takes hold, these changes in the brain erode a person’s self-control and ability to make sound decisions, while sending highly intense impulses to take drugs. Taking drugs becomes a matter of survival. These changes help explain the compulsive, destructive and often baffling behavior around addiction.

The behaviors associated with addiction look to healthy people like a lack of willpower because the primary symptom of addiction is irrational compulsivity. Someone who is sick with this disease will engage in risky and dangerous behaviors despite serious consequences because of these profound changes in the brain. 


“…addiction is not about drugs, it’s about brains. It is not the substances a person uses..; it is not even the quantity or frequency of use. Addiction is about what happens in a person’s brain when they are exposed to rewarding substances or rewarding behaviors, and it is more about reward circuitry in the brain and related brain structures than it is about the external chemicals or behavior that “turn on” that reward circuitry.” 

--American Psychiatric Association