It's pretty well established that using cannabis while the brain is still developing has a negative impact on brain development. Additionally, from what I've ob

It's pretty well established that using cannabis while the brain is still developing has a negative impact on brain development. Additionally, from what I've observed among a few dozen people I've known over the years, people who start smoking in high school and continue without any substantial breaks through to adulthood tend to have a less healthy relationship with cannabis. They have a stronger tendency to fall into the pattern of using all day every day, and tend use much larger amounts than people who started using as adults or have taken substantial breaks (year +) from cannabis consumption as adults.