Ironically, alcohol is probably the biggest offender when it comes to these sorts of problems. There is no reason to believe legalized cannibis or even most other drugs would have the same consequences. If you want to make people aggressive, violent, and destuctive, give them booze. If you want them buying munchies at the 7-11, give them pot.I'd argue it has to go beyond medical expenses because there are very real social expenses. The number escapes me right now but last year I read an article outlining how much money alcohol costs every week in the UK in terms of; vandalism (broken street furniture, shop windows etc), mess (litter, vomit, urine), extra policing etc.