"I thought it was for guys that did needles": Medication perceptions and lay expertise among medical research...

Although randomized controlled trials (RCTs) examine "objective" indicators of safety and efficacy of investigational drugs, participants may not perceive study medications as neutral entities. Some medications are imbued with social and cultural meaning, such as stigmatized medications for opioid use disorders. Such perceptions surrounding substance use treatments can extend to the research context and shape RCT participants' experiences with and adherence to study medications.

Considering these complexities in substance use research, we conducted a nested qualitative study within a multi-site, pragmatic RCT in Canada testing two treatments (methadone versus buprenorphine/naloxone) for opioid use disorder. Between 2017 and 2020, we conducted 115 interviews with 75 RCT participants across five trial sites in British Columbia, Alberta, Ontario, and Quebec.

Using an abductive coding approach, we characterized participants by their previous experience with medication for opioid use disorder and by their exposure to drug culture and drug scenes. Across these experience types, we identified systematic differences around participants' perceptions of the study medications, sources of information and expertise, and medication stigma.

Our findings illustrate the critical importance of social context in shaping medication beliefs and study experiences among people who use drugs, with implications for the conduct of future RCTs in substance use.