Substance abuse and substance addiction are terms used to describe problematic behaviors associated with the use of drugs or alcohol. Though these terms are sometimes used interchangeably, they refer to different aspects of substance use disorders.
Substance Abuse: Also known as drug abuse, refers to the harmful or hazardous use of psychoactive substances, including alcohol and illicit drugs. Substance abuse can be an isolated event or a pattern of behavior where an individual consumes substances in amounts or with methods that are harmful to themselves or others. It can lead to physical harm, issues at work or school, and problematic behavior. However, a person can abuse substances without being addicted to them.
Substance Addiction: Also known as drug addiction, is a chronic, relapsing disorder characterized by compulsive drug seeking and use despite adverse consequences, as well as long-lasting changes in the brain. It is considered a brain disorder because it involves functional changes to brain circuits involved in reward, stress, and self-control. Addiction is the most severe form of a full spectrum of substance use disorders, and is a medical illness caused by repeated misuse of a substance or substances.
Key signs of addiction can include physical dependence (experiencing withdrawal symptoms when not using the substance), tolerance (needing more of the substance to achieve the same effect), and inability to stop using the substance despite negative consequences.
It's also important to note that the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5), uses the term "substance use disorders" with specified severity levels (mild, moderate, severe) instead of the terms substance abuse and substance addiction, to provide a more precise diagnostic framework.