The American Psychiatric Association has published multiple iterations of the Diagnostic and Statistical Manual of Mental Disorders since 1952. While its latest edition, DSM-5, clearly outlines diagnostic criteria and classification of substance use disorders, the definitions have evolved with time. The current criteria assess for impaired control, use despite consequences, and clinical signs of neuroadaptation to determine disorder severity. These criteria are applicable to disordered use of many psychoactive substances. Standardized definitions facilitate communication of disease progression on the continuum that is substance use disorder.