Drug addiction, also called substance use disorder, is a disease that affects a person's brain and behavior and leads to an inability to control the use of a legal or illegal drug or medicine. Substances such as alcohol, marijuana and nicotine also are considered drugs.

Addiction treatment to reduce substance abuse commonly consists of a combination of group and individual therapy sessions that focus on teaching those in recovery the skills needed to get and stay sober as well as how to navigate various situations without turning to drugs or alcohol.