Casual marijuana use in teens isn’t harmless. Here’s why experts say parents should be ‘very concerned.’

Marijuana continues to be legalized across the U.S., with 22 states and Washington, D.C., allowing for the legal use and sale of the drug. With that, there seems to be a general consensus that marijuana (aka cannabis) is a relatively harmless drug. But a new Columbia University study suggests otherwise, especially for teens.

The study, which was published in the Journal of the American Medical Association (JAMA), analyzed data from more than 68,000 teens involved in the National Survey on Drug Use and Health, which collects data each year on tobacco, alcohol, illicit drugs and mental health. The researchers discovered that non-disordered cannabis use (i.e. using marijuana but not being addicted to it) was about four times more common than cannabis use disorder (a condition where people are unable to stop using marijuana even though it causes health and social problems in their lives). But the researchers also found that both were “significantly associated” with psychiatric disorders.

Specifically, teens who use cannabis recreationally were two to three times more likely to be diagnosed with depression and to have suicidal thoughts than those who don't use pot at all. Teens who have cannabis use disorder were four times more likely to have mental health disorders than non-users.

The researchers also found a link between cannabis use and poor academic performance, skipping school and legal issues.

"Kids, year by year, have been moving towards a view that marijuana is safe and benign — that’s factually incorrect," lead author of the study, Dr. Ryan Sultan, an assistant professor of clinical psychiatry at Columbia University, tells Yahoo Life. Sultan is a child psychiatrist and points out that he's seen more kids getting high before school than in the past.

Sultan’s study originally looked at teens who are addicted to cannabis but later expanded to those who use the drug recreationally. He says it was "very surprising" to see that these recreational users had a much higher risk than non-users of developing mental health issues. "We typically think of recreational use as not being a concerning behavior," he says.

That raises a lot of questions for parents about how concerned they should be, as well as what to do going forward. Here's what you need to know.

How concerned should parents be?

Sultan says that parents should be “very concerned” about the findings. “Some parents I work with ignore or condone that behavior. They don’t think about cannabis use as concerning, but it is,” he says.

Dr. Danelle Fisher, chair of pediatrics at Providence Saint John’s Health Center in Santa Monica, Calif., agrees. “I think the numbers are off — I think more kids are smoking pot than they’re letting on and this is an even bigger problem,” she tells Yahoo Life. “Marijuana affects the developing brain, and kids’ brains develop up until they’re 25 years old. Mental health is such an issue — this can make it worse."

Why might teen marijuana use impact mental health?

Sultan’s study didn't explore why cannabis use is associated with more mental health complications — it simply found a link. However, he says that cannabis use tends to feed into an unhealthy cycle with conditions such as depression and anxiety.

“Take a kid who is having some trouble and is at risk for depression: He gets an exposure to cannabis while he’s younger and feels less stress. Then it happens more and starts to waken his mind to this feeling that the substance makes him feel better,” Sultan says. “The more you use it, the more it negatively affects your thinking. That’s increasing the likelihood of depression and more suicidal thoughts. It’s feedback that spirals downward and gets to a place that really concerns us as child psychiatrists.”

This also brings up the larger question of which comes first: the mental health conditions or the pot use. Experts say it’s a little more complex than that. “Most of the time, people use certain substances to numb some of the emotions and the feelings that they have,” Dr. Muhammad Zeshan, clinical assistant professor of psychiatry at Rutgers New Jersey Medical School, tells Yahoo Life. In the case of teens, that can be related to peer pressure or other stressors, he says, noting that cannabis “can help them feel relaxed, calm and happy, making them more likely to use it again.”

But Zeshan says the issue is more in-depth than saying that teens with mental health disorders are more likely to reach for marijuana. “There are a lot of factors that go into this,” he says.

Fisher agrees. “There is definitely a subset of kids with mental health issues who are looking for ways to self-medicate,” she says. “But marijuana also might unmask depression or suicidality in kids who previously hadn’t expressed it.”

What can parents do?

The messaging around marijuana over the past few years has been that it’s a relatively safe drug, Sultan says, and he encourages parents to talk to their kids about why that's not true. “Parents need to educate their kids on this,” he says. “Parents need to be looking at cannabis use, as well as their kids having an increased risk of depression and anxiety. Your radar needs to be up that they’re much more likely to have issues learning, depression and anxiety, and not assuming that it’s not problematic or ‘just a phase.’”

Fisher suggests that parents “talk to your kids frankly about the exposure of their brain to this substance and that it can lead to a lot of worsening of things.”

If you discover that your child is using pot, Zeshan recommends using a more compassionate approach to talking to them about their use. “Try to sit with your children and understand why they’re using it,” he says. “Then, try to help them. Are there any other ways to cope with peer pressure and stress? Rather than punishing them, be more understanding and try to meet them where they’re at.”

But experts stress that it’s important to address pot use and its potentially harmful effects with kids. “It’s scary,” Fisher says. “I don’t think we should dismiss this.”

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