How have definitions of prescription drugs (including pain relievers and opioids) changed over time?

A number of updates to NSDUH have changed definitions of prescription drug use and disorders over time. In 2015, NSDUH underwent a redesign, and questions were updated about the use of prescription psychotherapeutics, including pain relievers, stimulants, sedatives, and tranquilizers. This also changed the definitions of opioid and methamphetamine use and created a trend break for these substances. More details on these changes are available from the 2014 and 2015 Redesign Changes report.

Additional changes have happened since then for use disorder measures. In 2020, the substance use disorder (SUD) section of the questionnaire was updated to reflect the definitions in the DSM-5, breaking trends with previous definitions of prescription drug and opioid use disorders. This included the addition, in 2021, of SUD among users of prescription drugs who did not misuse them (i.e., did not use them in a way not prescribed by a doctor). These use but not misuse summary measures were only produced in 2021. 

However, the underlying definitions of prescription drug use and misuse did not change between 2015 and 2023, even if data from 2020 and 2021 cannot be compared to previous years due to the addition of web response option to the survey.