As marijuana laws continue to change, it can be easy to assume that cannabis is no longer a serious concern, especially for young people. But changes in legislation do not change how marijuana affects the adolescent brain. In fact, new research suggests that even occasional use can have real consequences for teens.

A national study led by researchers at Columbia University Vagelos College of Physicians and Surgeons found that teens who used cannabis just once or twice a month were more likely to experience emotional distress and academic difficulties than those who did not use at all. The study examined data from more than 160,000 middle and high school students across the country and found a clear trend: as cannabis use increased, so did problems with mood, focus, and school engagement.

This is especially important because adolescence is a critical time for brain development. The parts of the brain responsible for learning, judgment, impulse control, and emotional regulation are still taking shape. Researchers involved in the study emphasized that using cannabis during this period, even casually, can interfere with those processes. Teens who used marijuana infrequently reported higher levels of anxiety, depression-like symptoms, and impulsive behavior. Those who used it more often were far more likely to struggle academically and disengage from school.

Another factor is potency. Today’s marijuana products often contain significantly higher levels of THC than in the past. Higher potency increases the risk of anxiety, difficulty concentrating, mood changes, and reduced motivation. Some teens may experience worsening mood or withdrawal symptoms after only limited use.

As marijuana becomes more normalized, teens may underestimate the risks. That’s where parents matter most: staying informed, setting clear expectations, and keeping conversations open. Even when they feel uncomfortable, they can make a real difference. Laws may change, but protecting young people remains just as important.