It is already happening.
ADHD results in wiring in the human brain that does not cease creating connections when a child approaches 21-years of age as is normal. Instead, the brain continues creating connections until the age of 24 to 26. That is why it is important to prevent youngsters from using illegal drugs and alcohol before they are in their late 20s.
The amazing thing here is that brain capacity can be expanded within the braincases many of us already possess.