The study was published in the journal "Addiction Biology" in August 2021. It used diffusion tensor imaging (DTI) to compare whole-brain white matter microstructure among 39 near daily cannabis users and 28 controls closely matched on age, sex, alcohol use, cigarette use and mental health.
"These findings suggest that long-term near-daily cannabis use does not necessarily affect white matter microstructure, but vulnerability may be higher during adolescence.
There does seem to be enough concern about cannabis use and adolescent brain development to warrant extreme caution. Adolescents should try to refrain from cannabis use unless directed to do so by a doctor.