A systematic review published in The Journal of the American Medical Association looked at all randomized controlled trials of cannabis or cannabinoids to treat medical conditions. They found 79 trials involving more than 6,400 participants. Medical marijuana prevented nausea and vomiting due to chemotherapy (47% of those using it versus 20% of controls). However, the combined trials did not show that it helps with psychosis, glaucoma, depression, dementia, epilepsy, Tourette’s syndrome or schizophrenia. Via The New York Times. Posted July 20, 2015.