To our knowledge, this is the largest study to date examining relationships between cannabis exposure (ever vs. never used) and brain volumes. Cannabis exposure was associated with smaller left amygdala and right VS volumes; these findings persisted even after controlling for a host of covariates. While other studies have noted reductions in amygdala volumes26-28, the right VS finding is somewhat unique to this study. It contradicts the increased VS volume in occasional cannabis users reported by Gilman and colleagues7. It remains to be explored whether this is due to the cannabis measures explored (e.g. cannabis-exposed vs. joints/week), sample size (483 vs. 40), or other sample characteristics (e.g. ethnicity; 74.5% White in our sample but unreported by Gilman et al.).
