Conflicts of Interest Among Systematic Review Authors for Cannabis Use Disorder Treatments

Marvin Carr, Vaishnavi Reddy, J Michael Anderson, Michael Weaver, Micah Hartwell, Matt Vassar

Research output: Contribution to conferencePosterpeer-review


Importance: Cannabis is the most commonly used illicit drug worldwide. In addition to potential adverse effects, those who use cannabis recreationally may develop a cannabis use disorder (CUD).

Objective: To evaluate disclosed and undisclosed conflicts of interest (COIs) and industry sponsorship’s influence on CUD treatment within systematic reviews.

Design, Setting, Participants: This cross-sectional developed a search strategy using Ovid, MEDLINE, and Ovid Embase for systematic reviews and meta-analyses focused on CUD treatment in June 2020. Following title and abstract screening, these reviews were evaluated for COIs per previously developed classification scheme. Study characteristics reviews were performed in duplicate fashion.

Interventions: Pharmacologic and nonpharmacologic

Main outcome and measure: Our primary objectives were to (1) evaluate the presence of disclosed or undisclosed COI of systematic review authors, regarding treatment of CUD; and (2) determine whether overall summary effect estimates, narrative results and conclusions were influenced by the presence of disclosed or undisclosed COI(s) among systematic review authors. Our hypothesis was developed before data collection.

Results: Our systematic search returned 560 articles which 9 systematic reviews were eligible for data extraction. We found 77.8% (7/9) contained at least one author with a COI. From the 51 authors included, 29.4% (15/51) were found to have a COI. Forty-four percent (4/9) were funded, 22.2% (2/9) were not funded, and 33.3% (3/9) had no funding statements. Out of the 7 systematic reviews with one or more authors containing COI, 14.2% (1/7) included results favoring the treatment group and 28.6% (2/7) included conclusions favoring the treatment group. Our results showed no significance between funding source and results (p = 0.429) or conclusions. Additionally, we found no significance between the presence of COIs with the favorability of results (p = 0.56) or conclusions.

Conclusion and relevance: Multiple studies favored treatment of cannabis-containing products, even though COIs were found in majority of the systematic reviews. COIs have the ability to sway results of a study, which can affect clinical decision-making. Stricter guidelines should be enforced among authors displaying COIs in systematic reviews studying CUD treatment.
Original languageAmerican English
StatePublished - 22 Feb 2021
EventOklahoma State University Center for Health Sciences Research Days 2021: Poster presentation - Oklahoma State University Center for Health Sciences Campus, Tulsa, United States
Duration: 22 Feb 202126 Feb 2021


ConferenceOklahoma State University Center for Health Sciences Research Days 2021
Country/TerritoryUnited States


  • Industry Sponsorship
  • Conflict of Interest
  • Cannabis Use Disorder
  • CUD
  • Cannabis
  • Systematics


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