The story here:
http://www.freerepublic.com/focus/news/2969335/posts?page=1
says this kid was on Fanapt, a schizophrenia drug.
Unsurprised.
http://www.freerepublic.com/focus/news/2969335/posts?page=1
http://www.nydailynews.com/news/national/nancy-lanza-feared-son-adam-worse-article-1.1221505
Neither link mentioned fanapt when I tried to find it.