Disproportionate increase in cannabis use among individuals with serious psychological distress and association with psychiatric hospitalization and outpatient service use in the National Survey on Drug Use and Health 2009-2019

AimsEstimate trends in levels of cannabis use among adults with and without serious psychological distress (SPD) in the United States from 2009-2019, and to ascertain whether cannabis use among individuals with SPD was associated with inpatient psychiatric hospitalization and outpatient mental health care. DesignUsing multivariable logistic regression models and predictive margin methods, we estimated linear time trends in levels of cannabis use by year and SPD status and rates of psychiatric hospitalization and outpatient service use. SettingThe United States: National Survey on Drug Use and Health (NSDUH), an annual cross-sectional survey, 2009-19 public use files. Participants447,228 adults aged [&ge;] 18 years. MeasurementsIn the past year, self-report of any and greater-than-weekly cannabis use, any inpatient psychiatric hospitalization, and any outpatient mental health care. FindingsRates of any and weekly-plus cannabis use increased similarly among individuals with SPD compared to those without from 2009-2014 but more rapidly in SPD from 2015-2019 (p<0.001). Among individuals with SPD, probability of psychiatric hospitalization was greater among individuals with less than weekly (5.2%, 95% CI 4.4-5.9%, p=0.011), and weekly-plus cannabis use (5.4%, 95% CI 4.6-6.1, p=0.002) compared to no use (4.1%, 95% CI 3.8-4.4%). For outpatient mental health care, no use was associated with a 27.4% probability (95% CI 26.7-8.1%) of any outpatient care, significantly less than less than weekly use (32.7% probability, 95% CI 31.3-34.1% p<0.001) and weekly-plus use (29.9% probability, 95% CI 28.3-31.5% p=0.006). ConclusionsCannabis use is increasing more rapidly among individuals with SPD than the general population, and is associated with increased rates of psychiatric hospitalization as well as increased outpatient service use. These findings can inform policy makers looking to better tailor regulations on advertising for medical and adult use cannabis and develop public health messaging on the use of cannabis in people with mental illness.