State-level marijuana policies and marijuana use and marijuana use disorder among a nationally representative sample of adults in the United States, 2015-2017: Sexual identity and gender matter.

Background: Research demonstrates an association between state-level medical marijuana laws (MMLs) and increased marijuana use (MU) and MU disorder (MUD) among adults, but has yet to explore this association among lesbian, gay and bisexual (LGB) individuals, including gender differences.

Methods: We pooled the 2015-2017 National Survey on Drug Use and Health data for adults (n = 126,463) and used gender-stratified adjusted multivariable logistic regression to model the odds of past-year MU, past-year medical MU, daily/near-daily MU, and MUD; we also tested the interaction between MML state residence and sexual identity.

Results: Bisexual women had higher past-year MU (40% versus 10.3%; aOR = 2.9[2.4-3.4]), daily/near-daily MU (9.8% versus 1.5%; aOR = 4.6[3.3-6.2]), and medical MU ((5.5% versus 1.2%) aOR = 5.5[3.8-8.1]) than heterosexual women. Gay/lesbian women also had higher past-year MU (26.1% versus 10.3%; aOR = 2.8[2.2-3.7]), daily/near-daily MU (5.6% versus 1.5%; aOR = 2.9[1.8-4.6]), and medical MU (4.7% versus 1.2%; aOR = 3.0(1.4-6.6]) than heterosexual women. Bisexual women in MML states had higher past-year MU ((44.4% vs. 34.1%); aOR = 1.8[1.5-2.1]) and medical use (7.1% vs. 3.3% (aOR = 2.5[1.5-3.9]) than bisexual women in non-MML states. The odds of any past-year medical MU for bisexual versus heterosexual women was different in MML versus non-MML states (Exponentiated β = 0.53, p = 0.01). Gay men in MML states had higher past year MU (31.2% versus 25.7%; aOR = 1.6[1.1-2.5] and medical MU (6.4% vs 1.7%; aOR = 5.0[4.2-6.1]) than gay men in non-MML states.

Conclusions: Results suggest that MMLs may differentially impact MU for sexual minority individuals-particularly bisexual women. Findings demonstrate the need for states enacting MMLs to consider potential differential impacts on LGB populations.