The brain develops most during childhood and adolescence, and this study goes into detail on which periods of youth are most important for growth. Gray matter in the brain is very important for controlling a person’s movement, memory, and emotions among other things. A key conclusion this study found was that brain growth stops in the third decade for nearly all adults.

The claim that the brain is not fully developed until 25 years old is generally true and it is important to keep a child’s brain healthy as they grow.