Gender and Age Differences in Comorbid Cannabis Use Disorders and Suicidality in a National Sample

Abstract

Approximately 40 million adults use marijuana annually, making marijuana one of the most commonly used substances in the United States (SAMHSA, 2019). Men and emerging adults (ages 18-25) report higher prevalence of cannabis use disorders (CUDs) relative to women and older adults (CBHSQ, 2015; Khan et al., 2013). More frequent marijuana use is associated with greater likelihood of suicidal ideation (Ilgen et al., 2009), and past year use in emerging adults is associated with future suicide attempts (Pedersen, 2008). Similar to correlates of marijuana use, emerging adults and men have higher rates of suicidality (SAMHSA, 2019; Krug et al., 2002). Limited research has tested gender and age differences in comorbid CUDs and suicidality. The current study evaluated gender and age differences in CUDs only, suicidality only, or comorbid CUDs and suicidality in a national sample of adults. We hypothesized that men and emerging adults would be over-represented in comorbid CUDs and suicidality and CUDs only groups. Data were from four consecutive years (2015-2018) of the National Survey of Drug Use and Heath. Multinomial logistic regressions tested gender and age differences in adults with DSM-IV cannabis abuse or dependence (CUDs) only, suicidality only, and comorbid CUDs and suicidality, all compared to adults with neither CUDs or suicidality. Four separate regressions were conducted for passive suicidal ideation, active suicidal ideation, suicide planning, and suicide attempts. Gender was coded as male or female. Age groups were 18–25, 26–34, 35–49, and 50 years or older. Analyses controlled for survey year, race/ethnicity, sexual orientation, education, household income, past year major depressive episode, past year DSM-IV alcohol abuse or dependence, and past year illicit drug abuse or dependence other than CUDs. Men disproportionately reported CUDs only (ORs=1.73-2.19, p<.001) and comorbid CUDs and passive suicidal ideation, active suicidal ideation, and suicide planning (ORs=1.72-2.12, p<.01), but not attempts (OR=1.16, p=.45) relative to women. Men reported 22% higher odds of active suicidal ideation than women. Women reported 15% higher odds of suicide attempts than men. Gender differences in passive suicidal ideation and planning were not statistically significant. Compared to older age groups, emerging adults were significantly more likely to report CUDs only (ORs=1.74-10.49, p’s<.01) and showed 2.36 to 14.24 times greater odds of comorbid CUDs and all four forms of suicidality (p<.001). Emerging adults were at 18% to 66% higher odds of either passive or active suicidal ideation alone compared to all older age groups (p’s<.001). This study investigated the relations between CUDs, suicidality, gender, and age in a nationally representative sample of adults. Results indicated that men and emerging adults consistently reported the highest likelihood of negative outcomes. Next steps include determining the direction of the relationship between CUDs and increasing severity of suicidality. Further, development and investment in programs for emerging adults with CUDs and suicidality are vitally important given the striking risk profile compared to other age groups. Future research should include program development and evaluation as well as gathering more information on risk and protective factors for these populations.