Scientists have confirmed the long-held suspicion that frequent heavy marijuana use damages the brain's memory and learning capacity. "Our results suggest that long-term cannabis use is hazardous to white matter in the developing brain. This was especially true for those who had started in adolescence, as we know the brain is still developing during this time," Lead researcher Dr. Marc Seal, from Melbourne’s Murdoch Children's Research Institute said in a university release. Scientists from MCRI, Melbourne University and Wollongong University compared MRI scans of the brain for 59 people who had been using marijuana for an average of 15 years...