Table 3.

Quality assessments and reported study limitations and conflicts

First author last name, year	Reported conflicts of interest	Reported study limitations	Q-Genie Score	Quality assessment
Cox, 2020	H.R.K. is a member of the American Society of Clinical Psychopharmacology’s Alcohol Clinical Trials Initiative, which was supported for the last three years by AbbVie, Alkermes, Ethypharm, Indivior, Lilly, Lundbeck, Otsuka, Pfizer, Arbor, and Amygdala Neurosciences. Drs. Kranzler and Gelernter are named as inventors on PCT patent application #15/878,640 entitled: "Genotype-guided dosing of opioid agonists," filed January 24, 2018. The funders had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript; or in the decision to publish the results	•Used cross-sectional data to study a phenotype that would require long-term follow-up to define cessation more accurately •Used a slightly different definition for cessation in the CATS dataset than in the Yale-Penn dataset •The opioid cessation GWAS sample had limited power to detect genome-wide significant association signals	63	Good quality
Nelson, 2016	Although unrelated to the current study, Dr Kranzler has been a consultant or advisory board member for Alkermes, Lilly, Lundbeck, Pfizer and Roche. He is also a member of the American Society of Clinical Psychopharmacology's Alcohol Clinical Trials Initiative, which is supported by Lilly, Lundbeck, Abbott and Pfizer. The remaining authors declare no conflict of interest	•Small size of control group (OUIP) •A more detailed characterization of the opioid use in the OUIP group was not obtained	45	Moderate quality
Smith, 2017	Dr. Kranzler reports being a consultant, continuing medical education (CME) speaker, or advisory board member for Alkermes, Indivior, Lundbeck, and Otsuka, and a member of the American Society of Clinical Psychopharmacology’s Alcohol Clinical Trials Initiative, which was supported in the last three years by AbbVie, Alkermes, Ethypharm, Indivior, Lilly, Lundbeck, Otsuka, Pfizer, and XenoPort	•Small sample size compared to mega-GWASs with pooled data •Daily methadone dose was self-reported	47	Good quality
Wang, 2018	None	•No statistically significant GWAS findings that pass the threshold p < 3.2 × 10–6 •Small sample size •Most subjects were male and 95% tested positive for HCV •Study was cross-sectional in design	44	Good quality
Yang, 2016	None	•Moderate sample size •Small replication sample—may not have detected significant associations (insufficient power)	53	Good quality