Addiction changes how the brain functions. It especially impacts the brain’s “reward system,” which is largely based on dopamine. This hormone is responsible for our pleasure response, along with other important functions like memory, attention, and mood.
Understanding addiction is an important part of recovery. Knowing there’s a physiological reason for your addiction can relieve some of the shame around it, so you can move forward in your healing journey. And gaining perspective on what’s driving your behavior can help you make lasting change.
We can experience pleasure from all kinds of activities, whether it’s exercise or scrolling social media. Our brain’s reward system is responsible for that feeling, and the desire to seek more of it.
Your brain produces a chemical called dopamine. Dopamine is both a hormone and a neurotransmitter, meaning it’s used to send messages between your nerve cells. It’s tied to many functions, from mood regulation and memory to learning. It’s known as the “feel-good” chemical for the large role it plays in pleasure and motivation.
Dopamine is released along different neural pathways when we anticipate and experience something pleasurable.1 As it’s released, it affects dopamine receptors that live along these pathways, resulting in feelings of euphoria or happiness. This is known as the reward circuit.
The reward circuit activates areas of the brain that relate to focus, learning, taking action, and motivation.
The brain builds connections between a stimulus and pleasure that follows.2 Your reward circuit strengthens each time this process occurs. The more frequently it happens, the stronger your response is. Also called a reinforcing effect, it’s involved in how we form habits.3
Cues leading up to pleasure are important. Dopamine makes us pay attention to markers that lead to a reward. This means dopamine activates before you even engage in a pleasurable activity.
This system helped early humans survive by rewarding beneficial behaviors, like eating. When it’s in balance, it allows us to stay focused, motivated, and happy. Dopamine imbalance is linked to mental health issues, like depression, and substance use disorders.
Substances bypass the body’s natural dopamine production by directly flooding the reward system with it. Some substances do this more intensely than others:
Stimulants like cocaine can release up to 10 times the amount of dopamine your body would naturally produce.4
The first time a substance is used, it creates a direct dopamine response. This intensity of this varies from person to person. According to neurotheology specialist Dr. Cyrus H. McCandless, “you can never accurately predict how much reward you’re going to get.”5
Your brain remembers everything leading up to a reward, so it can repeat the experience. This drives the desire to use more of a substance. As dopamine levels go up, serotonin, which helps us feel satisfied, goes down. This creates a cycle of wanting more while feeling less satiated.
This cycle doesn’t just apply to substance use. Altered dopamine pathways are seen in behavioral addictions,