The Office of the Surgeon General and the Substance Abuse and Mental Health Services Administration (SAMHSA) developed this from the Surgeon General’s Report, in order to provide opioid-related information in one, easy-to-read document. Although does not include new scientific information, it provides the latest data on prevalence of substance use, opioid misuse, opioid use disorders, opioid overdoses, and related harms. This document sometimes discusses substance use disorders rather than opioid use disorder specifically. As indicated in the section “The Neurobiology of Substance Use, Misuse, and Addiction,” opioids and other substances have similar effects on the brain’s reward pathways. Additionally, it is common for people who misuse opioids to misuse other substances or to have multiple substance use disorders or co-occurring mental disorders. Therefore, the general principles related to substance use disorders often apply to opioid use disorder.