In the final years of maturation, there is a plateau.
We know that the earlier in life dependence occurs, the stronger it will become, because of the fact that the brain is perhaps more malleable and that habits are acquired at a younger age. As a consequence, the later cannabis consumption begins, the less dependence will develop.
In addition, it may be that, at 21, people have become socially and individually mature. At that age, they are sometimes looking at setting the course for their lives. It may be that education and information programs have allowed them to recognize the dangers associated with consuming cannabis and that they have become somewhat afraid of it.
The information and education that we have to provide to young people must also be closely linked to the research being done in the area. We are in the process of legalizing a product that, as scientists, we know little about in a number of respects. There is still a lot we do not know about this product and its effects.