March 11, 2019&mdash;Teens who use marijuana are at increased risk for depression and suicide when they become young adults, a new review of several studies suggests.

Researchers looked at 11 previous studies of about 23,000 people around the world. They considered daily to occasional cannabis use among the people who took part in these studies. 

The researchers said that while each teen marijuana user was only at modest risk, for youths overall, the risk to mental health could be significant. In fact, the study's findings suggest that more than 400,000 cases of depression in young U.S. adults ages 18 to 32 could be tied to their earlier marijuana use.

Marijuana use was also linked to a raised risk of suicidal thoughts or attempts. 

Caution: Young brains under construction 

Marijuana is the most widely used drug, the researchers noted. And it has grown in popularity. About 7 percent of high school students say they use marijuana daily or almost every day. But we're still learning about the effects of marijuana on a teen's developing brain. The brain continues to develop into a person's early 20s. During that time, the brain may be more vulnerable to substance use. 

To be sure, depression can have many causes, the researchers noted. But the study suggests that marijuana use could be one of the factors that contributes to depression in young adults.

Helping kids say no

For parents, the findings offer a vital message: Talk with your preteen or teen about the risk of using marijuana. Besides the concerns raised in this study, marijuana use has also been linked to a number of other risks. Among them: poor grades, addiction, psychotic disorders, car crashes and breathing problems.

The study was <a target="_blank" href=" https://jamanetwork.com/journals/jamapsychiatry/article-abstract/2723657"> published in JAMA Psychiatry</a>.

Teen marijuana use tied to adult depression