Higher-Potency Cannabis Use Associated With Cannabis Use Problems and Generalized Anxiety Disorder in Young Adults
Cannabis use is associated with poor mental health outcomes, and higher cannabis potency may be associated with greater mental health risks. This cross-sectional study examined the association of higher-potency cannabis use and substance use and mental health measures in a UK birth cohort of 24-year old participants who reported past-year cannabis use (N=1087). The main exposure variable of most commonly used cannabis type was self-assessed and dichotomized by higher potency (“skunk/other stronger types of herbal cannabis”) and lower potency (“herbal cannabis/marijuana” or “hashish/resin/solid” or “other”).
- Higher-potency cannabis use was significantly associated with an increased frequency of cannabis use (adjusted odds ratio [aOR], 4.38), and increased odds of cannabis use problems (aOR, 4.08) and generalized anxiety disorder (aOR, 1.92), compared with lower-potency cannabis use.
- Higher-potency cannabis use was NOT associated with use of other illicit substances, alcohol use disorder, major depression, and psychotic experiences, after adjusting for childhood sociodemographic factors, mental health measures during adolescence, and frequency of cannabis use.
Comments: Higher-potency cannabis use was associated with increased frequency of cannabis use, cannabis use problems, and generalized anxiety disorder in this cross-sectional study, but the direction of causation is unclear. Given the growing availability of high-potency cannabis, further study of its risks is needed.
Tae Woo (Ted) Park, MD
Reference: Hines LA, Freeman TP, Gage SH, et al. Association of high-potency cannabis use with mental health and substance use in adolescence. JAMA Psychiatry. 2020;77(10):1044–1051.
One comment
Hi,
I am commenting on this as the lead author of the study, which has been very nicely summarised here. Hope you all enjoy it!
I would like to expand on two points. Firstly, the adolescent mental health measures we adjusted for were psychostic-like experiences at age 12, and depression symptoms at age 13. These were measured prospectively.
Secondly, I would like to explain our apporach adjustment for cannabis frequency.
If using cannabis more frequently leads to people progressing to use of higher-potency cannabis (plausibly through the development of tolerance to the effects of cannabis), then it is appropriate to adjust for frequency of cannabis use as a confounding variable. However, if using higher-potency cannabis leads to individuals using cannabis more frequently, it would be statistically approprite to consider frequency of use as a mediator.
Unfortunately the relationship between use of higher-potency cannabis and frequency of use is not yet clear. As such, we took the cautious approach of presenting our results with and without adjustment for freqeuncy (we did not have the temporal data necessary to consider mediation).
Before adjustment for frequency of cannabis use (but maintaining adjustment for sociodemographic factors and adolescent mental health) we found similar effect sizes for the association between the use of high-potency cannabis and report of frequent or distressing psychotic experiences (not associated with drug use) as those observed in case-control studies of first-episode psychosis (AOR 1.86, 95% CI 1.00-3.46). However, in our study, we observed a substantial attenuation in effect size, by approximately 66%, after adjustment for frequency of cannabis use.
Given higher frequency of cannabis use is a known risk factor for mental health outcomes, I would suggest that future studies take a similar apporach.