Substance Use Addiction
Abuse of substances such as alcohol, marijuana, cocaine, prescription medications, and others can cause health issues and serious problems with family, friends, coworkers, job, money, and the law. Yet despite these problems, use of the substance continues.
Why? Addiction is a physical dependence on a chemical substance. The dependence leads to unpleasant symptoms, called withdrawal, when a person stops using the substance. People often begin using an addicting substance because it initially gives them pleasure. By the time addiction has developed, the pleasure is often gone. The driving force behind continued use is a need to avoid the unpleasant symptoms of withdrawal.
Source: Harvard Health