This is downright silly .
It will just point to most introverts .
Newsflash their are millions of introverts and just because they don’t socialize doesn’t make them lonely.
It certainly doesn’t make school shooters.
She is asking the wrong questions .
You want to look for the angry kid and he may or may not be an introvert . You can lay odds the kid has problems at home and there is a good chance he gets picked on at school too.
Being on medication is big hint too.
Statistically, introverts, as a group (there's always exceptions) score significantly lower on:
--satisfaction in marriage
--satisfaction in work
--make less money
--I forget the 4th thing ... might be satisfaction with life in general.