21+ — how the age limit was decided

The age limit for cannabis use in Grenada is 21 and over. But how was this number decided? What were the alternatives considered?

Many countries use 18 (the age of majority), while others use 21 (aligned with alcohol in some jurisdictions). The 21+ threshold reflects concerns about brain development — research suggests the brain continues developing into the mid-20s.

Do you think 21 is the right age? What factors should determine the legal age for cannabis use?