I think it can be agreed upon that Adam had some mental health issues. His own family admitted that. What would trigger him to kill his mother and 26 other people?

Apparently he lived on his own during the final days while his mother was in New Hampshire on vacation. A book on Aspergers Syndrome was found during a search warrant of his house. A plant, who knows? Aspergers in itself is not such a big issue.

The picture being painted of him is a shy 20 year old with high IQ but lacking in social skills. A shut in who enjoyed playing violent video games. Which in itself means nothing.

What triggered him to do what he did? Evidence obtained at the scene may reveal what happened in the final days.