Long-term drug use changes connections between neurons, rewiring brain circuits involved in judgment, learning, and memory.

As drug use continues, the brain’s neural pathways adapt to the persistent presence of the substance. Connections between neurons in areas like the nucleus accumbens, part of the reward system, increase in size and strength, reinforcing compulsive drug-seeking behavior. Simultaneously, brain regions responsible for critical thinking and memory may lose connections or function abnormally. These structural and functional changes make drug use habitual and automatic, turning voluntary use into addiction.