May 7, 2007 — Harvard Medical School publishes the results of a 4-year study on the effectiveness of marijuana as a pain-reliever. The result show a negative correlation between weed use and pain, with regular marijuana users showing more pain symptoms than non-users. This gives new ammunition for those opposing drug legislation and medical marijuana use in USA.
August 12, 2009 — a study is unveiled by the Universidad Nacional Autónoma de México linking cannabis use and psychosis.
OOC: basically the equivalent of these two studies appear ~10 years earlier in this TL due to more research into cannabis.
One was based in Australia though so not sure if it would’ve occurred earlier unless MM was approved even earlier