Those who had a behavorial condition, autism, or intellectual disability

If you can give a detailed description of their condition and how it affected them.

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Alek Minassian - Asperger's - Led to him being bullied in school, not being able to hold down a position in the Army and having an obsessive interest with computers and videogames such as Halo. Though it was noted he had a natural aptitude for computers and was thought of as 'brilliant' by his classmates after High School
Jake Davison - Asperger's - Led him to not understand why girls did not like him and see himself as socially unable to get a girlfriend due to his Asperger's.
I can't provide a detailed explanation for anyone else but some other shooters that had autism or a behavioral condition are:
- Brandon Scott Hole
- Chris Harper-Mercer
- Barry Loukaitis
- Nikolas Cruz

Adam also was a natural with computers. The Newtown book says he was the only student in his tech club that could build a computer from scratch. He also was deeply involved with online gaming. This seems to be a common theme with shooters... I'm not familiar with the others that you mention.

Jake Davison had autism and ADHD which effected his ability to form relationships.