Cannabis use, psychotic-like experiences, and vascular risk in young adults

There is a robust association between psychosis and cannabis use, but the mechanisms underlying this relation are poorly understood. Because both psychosis and cannabis use have been linked to cardiovascular problems, it is possible that cannabis use exacerbates an underlying vascular vulnerability in individuals prone to psychosis. To investigate microvascular differences in individuals with psychotic symptoms and cannabis use, the current study tested associations between psychotic-like experiences, cannabis use, and retinal vessel diameter in 101 young adults (mean age=19.37 years [SD=1.93]). Retinal venular diameter did not differ between participants with (M=218.08, SD=15.09) and without psychotic-like experiences (M=216.61, SD=16.18) (F(1, 97)=0.01, p=.93) or between cannabis users (M=218.41, SD=14.31) and non-users (M=216.95, SD=16.26) (F(1, 97)=0.37, p=.54). Likewise, mean retinal arteriolar diameter did not differ between participants with (M=157.07, SD=10.96) and without psychotic-like experiences (M=154.88, SD=9.03) (F(1, 97)=0.00, p=.97). However, cannabis users had statistically significantly wider retinal arterioles (M=159.10, SD=9.94) than did non-users (M=154.29, SD=10.20) (F(1, 97)=5.99, p=.016), and this effect was robust to control for covariates. There was no evidence of an interaction between psychotic-like experiences and cannabis use in predicting retinal vessel diameter. These results indicate that cannabis use is associated with microvascular differences in young adulthood. Given current trends toward legalization of recreational cannabis use, future research should explore these differences and their potential consequences for cardiovascular health.