Identical Twins Reveal Legalizing Recreational Cannabis Has Increased Frequency of Use by 20%
A recent study that appeared in the academic journal Addiction suggests that the legalization of cannabis for recreational use in some U.S. states has resulted in an average 20% rise in the frequency of cannabis use in those states. An extensive sample of adult identical twins was used in the study to evaluate the consequences of legalizing cannabis for recreational use. Particularly intriguing were the 111 identical twin pairings where one twin resided in a state with a different legalization of recreational marijuana than the other. Twin studies offer remarkably well-matched controls for one another in comparison to research on unrelated individuals, allowing for more accurate evaluation of the causal effect of legalizing recreational activities. Participants in the study comprised 1,425 people from states where marijuana use for recreational purposes is permitted and 1,997 people from places where it is outlawed. The study indicated that across all of them, legalization led to an in...