Opioid use disorder is a diagnosis listed in the chapter Substance-Related and Addictive Disorders in the Diagnostic and Statistical Manual of Mental and Emotional Disorders (DSM-5; American Psychiatric Association [APA], 2013). Opioid use disorder, like all substance use disorders (SUDs), is characterized by a loss of control over consumption of the substance, obsessive thoughts about the substance, and continued use despite negative consequences (APA, 2013). Opioid use disorder is diagnosed on a continuum from mild (i.e., two or three of the diagnostic criteria), to moderate (i.e., four to five of the diagnostic criteria), to severe (i.e., six or more diagnostic criteria).