Marijuana has a [b]low[/b] addiction rate [i]for adults[/i]. It's addiction rate is, on average, significantly higher for persons younger than 19. Marijuana lowers memory, reaction time, and mental processing speed, so basically it lowers IQ. Marijuana use also highly correlates with late development of depression and schizophrenia. Edit: I'm not saying I'm against legalization. I've used MJ, but I'm not ignorant to the potential health risks.