New research reveals marijuana users face 29% higher heart attack risk and doubled cardiovascular death chances, plus brain and sleep health impacts.

Dr. Smita Das often hears the same myth: You can’t get hooked on pot. And the misconception has become more widespread as a growing number of states legalize marijuana. Around half now allow recreational use for adults and 40 states allow medical use.

Shakespeare coined the word addiction to mean “strong inclination” toward any activity. People continue using the word in this general way, e.g., “television addiction.” I use addiction in the more limited sense of drug-induced changes in the brain ...