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Abstract
Background
Rates of cannabis use disorder (CUD) have increased disproportionately among Veterans Administration (VA) patients with psychiatric disorders compared to patients with no disorder. However, VA patient samples are not representative of all U.S. adults, so results on disproportionate increases in CUD prevalence could have been biased. To address this concern, we investigated whether disproportionate increases in the prevalence of cannabis outcomes among those with psychiatric disorders would replicate in nationally representative samples of U.S. adults.
Methods
Data came from two national surveys conducted in 2001-2002 (n = 43,093) and 2012-2013 (n = 36,309). Outcomes were any past-year non-medical cannabis use, frequent non-medical use (≥3 times weekly), and DSM-IV CUD. Psychiatric disorders included mood, anxiety and antisocial personality disorders. Logistic regression was used to generate predicted prevalences of the outcomes, prevalence differences calculated and additive interactions compared differences between those with and without psychiatric disorders.
Results
Cannabis outcomes increased more among those with psychiatric disorders. The difference in prevalence differences included any past-year non-medical cannabis use, 2.45% (95%CI = 1.29-3.62); frequent non-medical cannabis use, 1.58% (95%CI = 0.83-2.33); CUD, 1.40% (95%CI = 0.58-2.21). For most specific disorders, prevalences increased more among those with the disorder.
Conclusions
In the U.S. general population, rates of cannabis use and CUD increased more among adults with psychiatric disorders than other adults, similar to findings from VA patient samples. Results suggest that although VA patients are not representative of all U.S. adults, findings from this important patient group can be informative. Greater clinical and policy attention to CUD is warranted for adults with psychiatric disorders.
