> researchers were unable to account for several potential confounding factors including the duration and amount of cannabis use or the use of tobacco or other drugs.
Personally I'd wager a bet it's the tobacco and/or smoking that is the harmful part, but it kind of dumbfounds me they failed to account for "details" like "duration and amount of cannabis use", that feels like a very vital thing to control for. Nothing is good for you in too great amounts, even water, so not taking that into account seems to not really give reliable and trustworthy results.
Personally I'd wager a bet it's the tobacco and/or smoking that is the harmful part, but it kind of dumbfounds me they failed to account for "details" like "duration and amount of cannabis use", that feels like a very vital thing to control for. Nothing is good for you in too great amounts, even water, so not taking that into account seems to not really give reliable and trustworthy results.