First author, date	Data collection period (years)	Study design	Sample type	Sample Size	Reports on scope	Reports on motivations	Reports on outcomes
Alexander, 2020	2016–2018	Cross sectional	General population	898	Yes	No	No
Allen, 2016	2013–2015	Qualitative	PWUD	42	No	Yes	Yes
Applewhite, 2020	2018	Cross sectional	PWUD	103	Yes	No	No
Bachhuber, 2018	2011–2014	Retrospective cohort	PWUD	124	Yes	No	No
Bazazi, 2011	2009	Cross sectional	PWUD	100	Yes	Yes	No
Brown, 2014	2010–2012	Qualitative	Online discussion post forums	121 discussion board threads	No	Yes	No
Butler, 2018	2015	Cross sectional	PWUD	45695	Yes	No	No
Buttram, 2020	2018–2019	Cross sectional	PWUD	324	Yes	No	No
Carlson, 2020	2017–2018	Cross sectional	PWUD	356	Yes	Yes	Yes
Carroll, 2018	2016	Cross sectional	PWUD	128	Yes	Yes	No
Cicero, 2007	2005–2007	Cross sectional	People with OUD	799	Yes	No	No
Cicero, 2014	2008–2013	Cross sectional	People with OUD	10568	Yes	Yes	No
Cicero, 2018	2016	Cross sectional	People with OUD	303	Yes	Yes	No
Cunningham, 2013	2004–2009	Prospective cohort	People with OUD	87	Yes	No	Yes
Daniulaityte, 2012	2009–2010	Mixed Methods	PWUD	396	Yes	Yes	No
Daniulaityte, 2015	2005–2013	Qualitative	Online discussion post forums	404 posts	No	Yes	No
Daniulaityte, 2019	2017–2018	Cross sectional	People with OUD	356	No	Yes	Yes
Dart, 2014	2009–2011	Cross sectional	General population	13514	Yes	No	No
DiPaula, 2011	2012–2013	Prospective cohort	People with OUD	12	Yes	No	No
Fox, 2014	2011	Cross sectional	PWUD	102	Yes	No	Yes
Fox, 2014	2013	Cross sectional	PWUD	138	Yes	No	No
Fox, 2015	2012–2013	Qualitative	People on MOUD	21	Yes	No	Yes
Genberg, 2013	2008	Cross sectional	PWUD	602	Yes	Yes	No
Gryczynski, 2013	Not LIsted	Qualitative	People with OUD	80	Yes	Yes	Yes
Guo, 2013	2008–2011	Cross sectional	General population	20929	Yes	No	Yes
Gwin Mitchell, 2009	2004–2007	Qualitative	PWUD	22	Yes	Yes	Yes
Hood, 2020	2017	Prospective cohort	People on MOUD	146	Yes	No	Yes
Kavanaugh, 2020	2018	Qualitative	PWUD	40	Yes	Yes	No
Kenney, 2018	2017	Cross sectional	People with OUD	338	Yes	Yes	Yes
Khosla, 2011	2005–2006	Cross sectional	PWUD	1320	Yes	No	No
Ling, 2019	2015–2018	Prospective cohort	People on MOUD	533	Yes	No	No
Manubay, 2015	Not Listed	Cross sectional	People with OUD	205	Yes	No	No
McLean, 2019	2018	Qualitative	PWUD	20	Yes	Yes	Yes
Mitchell, 2015	Not Listed	Prospective cohort	People with OUD	300	Yes	No	No
Monico, 2015	Not Listed	Mixed Methods	People on MOUD	300	Yes	Yes	Yes
Monico, 2021	Not Listed	Qualitative	People with OUD	26	Yes	Yes	Yes
Monte, 2009	2007–2018	Cross sectional	PWUD	49	Yes	Yes	Yes
Otachi, 2020	2018–2019	Cross sectional	PWUD	324	Yes	No	Yes
Park, 2018	2016	Cross sectional	PWUD	203	Yes	No	Yes
Schuman-Olivier, 2010	2009	Cross sectional	People on MOUD	129	Yes	Yes	Yes
Silverstein, 2019	2018–2019	Qualitative	People with OUD	63	No	Yes	Yes
Silverstein, 2020	2017–2018	Qualitative	People on MOUD	65	No	Yes	Yes
Smith, 2007	2003–2005	Cross sectional	PWUD	103 million calls	Yes	No	No
Smith, 2019	2017	Cross sectional	People with OUD	478	Yes	Yes	No
Smith, 2020	2016–2018	Cross sectional	People with OUD	12007	Yes	Yes	Yes
Sohler, 2013	2010	Qualitative	PWUD	38	No	Yes	No
Surratt, 2018	2012–2015	Prospective cohort	People with OUD	172	Yes	No	Yes
Suzuki, 2017	2013–2014	Retrospective cohort	People on MOUD	168	Yes	No	No
Tofighi, 2014	2012–2013	Cross sectional	People on MOUD	91	Yes	No	No
Tofighi, 2019	2018	Qualitative	People with OUD	23	Yes	No	Yes
Tofighi, 2021	2020	Retrospective cohort study	People on MOUD	78	Yes	No	No
Tsui, 2018	2015	Cross sectional	PWUD	487	Yes	Yes	No
Walker, 2018	2015–2016	Cross sectional	People with OUD	896	Yes	Yes	Yes
Walley, 2019	2013–2015	Retrospective cohort	PWUD	2916	Yes	No	No
Wiegand, 2016	2011–2013	Retrospective cohort	PWUD	unknown	Yes	No	No
Wish, 2012	2010	Qualitative	General population	15	No	Yes	No
Zhao, 2020	2011–2013	Cross sectional	PWUD	777	Yes	No	Yes

Abbreviations: MOUD = medications for opioid use disorder; OUD = opioid use disorder; = PWUD = people who use drugs