INCREASE OF MENTAL ILLNESS

https://www.csbj.com/2017/09/15/the-health-effects-of-the-legalization-of-marijuana/
The Clarke paper controlled for a prior history of mood disorders and still found a 7-fold increased risk with marijuana use. 
The Agrawal paper studied twins to control for genetic confounders (though it was a little difficult to find twins who were completely discordant in their marijuana use) and found a 2.47-fold increase in suicidal thoughts for the twin who used regularly versus the twin who used lightly or not at all.
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A web site from Colorado - looking at suicide data:
https://cohealthviz.dphe.state.co.us/t/HSEBPublic/views/CoVDRS_12_1_17/Story1?:embed=y&:showAppBanner=false&:showShareOptions=true&:display_count=no&:showVizHome=no#4