“Marijuana use was also linked with a variety of factors known to increase cardiovascular risk, such as obesity, high blood pressure, smoking and alcohol use. After researchers adjusted the analysis to account for these factors, marijuana use was independently associated with a 26 percent increase in the risk of stroke and a 10 percent increase in the risk of developing heart failure.
Even when we corrected for known risk factors, we still found a higher rate of both stroke and heart failure in these patients, so that leads us to believe that there is something else going on besides just obesity or diet-related cardiovascular side effects, Kalla said. More research will be needed to understand the pathophysiology behind this effect.
https://www.livescience.com/56264-heavy-marijuana-use-may-damage-the-brain.html
Many legally prescribable medicines have unwanted side effects.