Using marijuana as a teen is associated with a higher chance of experiencing depression as an adult, according to a new study that adds to a growing debate over the health effects of marijuana.
Cannabis is the most popular drug for teens, who are increasingly turning to marijuana before alcohol and tobacco. Yet even as support for marijuana legalization grows, there has also been a push to highlight the downside and potential dangers of marijuana and mental health (including a much-hyped but poorly reported new book). For today’s study, published in the journal JAMA Psychiatry, researchers from McGill and Oxford Universities analyzed 11 studies that covered nearly 24,000 teens. They found that using marijuana at least weekly before 18 is associated with a 37 percent increased risk of depression in adulthood (up to age 32), even when taking into account someone’s existing mental