Differential effects of cannabis vapour constituents on brain connectivity: Exploring the long-term effects of adolescent exposure

Cannabis use is common in adolescence and there is evidence for sex differences regarding the long-term effect of cannabis use. We aimed to investigate how exposure to 3 types of cannabis vapour in adolescent rats impacts brain development using magnetic resonance imaging. Male and female Sprague Dawley rats were divided into four groups and exposed to high-CBD, high-THC, balanced CBD + THC, or air at post-natal days 28-42 using a vaporizer. In adulthood, rats underwent diffusion and functional MRI. Results indicated sex-dependent differences in the long-term effects of cannabis exposure in the adult brain. In male rats, we found a single network with altered functional connectivity amongst the four groups and two networks with altered structural connectivity amongst the four groups. In female rats, MRI results indicated no altered structural or functional networks. Adolescent cannabis vapour exposure can lead to long-lasting effects in adulthood, with males possibly being more vulnerable.