Unfortunately this research is based on self reporting and most like is the result of Cannabis Consumption that has High THC and virtual NO CBD which skews results dramatically.

Researchers claim that they can not verify the medicinal properties of cannabinoids because they can not isolate their individual effects yet when it comes to claiming the deleterious effects of cannabis use, they seem to have no issue assigning negative consequences to ALL cannabis use regardless of the varying concentrations of Cannabinoids.