The perception of marijuana has changed dramatically in recent years. With this change in perception, teens increasingly report a belief that marijuana is completely safe and, in fact, seem to believe it enhances their lives physically and mentally. Parents also seem more open to their children using marijuana. With all this in mind, I wanted to share what research has discovered about the impact of marijuana use for adolescents.

• Persistent marijuana use interferes with adolescent brain development. Individuals who started using marijuana in their teens and smoked persistently showed an average 8 point drop in their IQ between the ages of 18 and 38 years…even if they stopped using! Teen brains are not fully formed. They are still developing. And, persistent marijuana use interferes with their development. (Read study review here.)
• Some studies suggest that regular marijuana use during adolescence may increase the risk of developing serious psychiatric disorders such as schizophrenia. These same studies suggest that the areas of the brain associated with planning and impulse control are the areas experiencing greater long-term affects lasting into adulthood. (Read study review here.)
• Teens who smoke marijuana daily for about three years experienced poor working memory, which predicts poor academic performance, and results in poor performance on memory tasks. These decreases in ability lasted until at least the early 20’s—the college age when academic performance becomes increasingly important. The young adults who abused marijuana as teens (and were now two years marijuana free) performed about 18% worse on long-term memory tests than young adults who never abused marijuana. (Read study review here and another one here.)
• Individuals who started using marijuana prior to 16-years-old experienced arrested development in the prefrontal cortex, the areas of the brain responsible for judgment, reasoning, planning, and critical thinking. In other words, marijuana abuse beginning prior to 16-years-old interferes with the development of skills important to impulse control, planning, and academic performance. (Read study review here.)
• Marijuana use may interfere with a person’s ability to empathize with another person’s emotion. This, in turn, could greatly impact the ability to form intimate relationships. (Read study review here.)
• In one study, 18- to 25-year-olds who regularly used marijuana seemed to demonstrate impaired processing of social norms. They seemed less aware of social norms and exhibited a reduced capacity to reflect on or react to negative social situations. (Read study review here.)
• In another study, those in their mid-twenties who were heavy users of marijuana (using dependently for 7 years) exhibited a compromised dopamine system in their brain. Specifically, this could impact working memory, impulse control, and attention span. (Read study review here.)
• Marijuana use dampens the brain’s reward system over time. In other words, people who use marijuana feel less reward, less enjoyment, from positive, pleasurable experiences. This may increase their risk-taking behavior and the chances of addiction. (Read study review here.)
• Although teens often seem to believe marijuana use decreases their depressive symptoms, studies suggest that it has no effect on depression. In addition, marijuana use starting at a young age (under 17-years-old) led to “abnormal brain function in areas of the brain related to visual-spatial processing, memory, self-referential activity, and reward processing.” (Read study review here.)
• Many teens seem to think marijuana use enhances creativity. However, recent studies suggest that regular users of marijuana are worse at creative thinking. They also performed poorly on tests in which they had to detect their own mistakes. (Read study review here.)

More research needs done, but perhaps these studies can begin to help us gain some understanding of the potential effect of marijuana on our teens’ developing brains.