The brain can slowly rebuild itself if drug use stops.

The brain is incredibly bendy and can heal over time. This superpower is called neuroplasticity. When a person stops using drugs, the brain slowly begins to grow its dopamine receivers back. However, this is a slow walk. Brain scans of people who used to use drugs show that it can take a year or more of being clean for the brain's chemistry to look normal again. It is like waiting for a forest to grow back after a fire.