* Cancer causing and hereditary effects (http://www.drugfreeworld.org/drugfacts/marijuana/the-harmful-effects.html) * Lower life satisfaction, poorer mental health, poorer physical health, more relationship problems (https://www.drugabuse.gov/publications/drugfacts/marijuana) * Reduced IQ (https://www.drugabuse.gov/publications/marijuana/what-are-marijuanas-long-term-effects-brain) Doesn't seem good to me, and legalisation might send a message to those who would not otherwise us it that "it's ok" when it isn't.