You may be exactly right - it's known that the first place affected in the brain of smokers is the frontal lobe - the part of the brain that makes decisions re right or wrong.
Certainly, pot heads display this symptom...and, supposedly, the damage is irreversible - so would it not be plausible that there is a connection?
Has there been a study to determine the percentage of these victims that were into drugs when young? (Or would that be politically incorrect?)
................uh..........what?.............