Heavy marijuana use over a number of years can cause significant brain abnormalities, damage memory and emotional processing, and even shrink parts of the brain, the Age reports. All cannabis smokers—not just high-risk groups such as the young and those susceptible to mental illness—can experience effects equivalent to those of a mild brain injury, Australian researchers found.
"If you're using cannabis daily, heavily and over a long period of time, the people in this study had been using for about ten years, then you are likely to have changes in the brain that are likely to lead to or mimic some of the symptoms of things like paranoia, memory loss, confusion," an expert told ABC News of Australia. (More marijuana stories.)