A report from the American Academy of Pediatrics (AAP) found that teenagers increasingly believe marijuana is safe to use since more states have legalized the drug for adult use. This is despite concerns by medical professionals that the drug is detrimental to brain development during adolescence.

Along with an impression among teenagers that the drug is completely harmless, the trend is leading to rising drug use among the same age group.

The National Survey on Drug Use and Health found, “The percentage of youths aged 12 to 17 perceiving great risk in smoking marijuana once or twice a week decreased from 54.6 percent in 2007 to 39.5 percent in 2013.” It also found that a decrease in perceived risk typically precedes an increase in use.

Yet there are significant risks with using marijuana, especially among teenagers. According to the AAP report, “The adolescent brain, particularly the prefrontal cortex areas that control judgment and decision-making, is not fully developed until the early 20s, raising questions about how any substance use may affect the developing brain.”

The report outlined the risks, including “impaired short-term memory and decreased concentration, attention span, and problem-solving skills, all of which interfere with learning.”

In addition, “Alterations in motor control, coordination, judgment, reaction time, and tracking ability have also been documented.”

According to AAP, studies show that long-term risks of marijuana use by adolescents include “executive function and cognitive speed,” which “did not recover by adulthood, even when cannabis use was discontinued.”

“As with other psychoactive substances, the younger an adolescent begins using drugs, including marijuana, the more likely it is that drug dependence or addiction will develop in adulthood. Evidence clearly shows that marijuana is an addictive substance; overall, 9% of those experimenting with marijuana will become addicted; this percentage increases to 17% among those who initiate marijuana use in adolescence and to a range of between 25% and 50% among teenagers who smoke marijuana daily.”

Matthew Smith, a research assistant professor at Northwestern University’s Feinberg School of Medicine in Chicago, stated to Time magazine: “Adolescence is a sensitive time for brain development. If a teen introduces the abuse of marijuana at that point in their life, it could have consequences for their ability to problem solve, for their memory and for critical thinking in general.”