Someone said in a recent comment (seems to be gone now, or else I just can't find it - been trying) that Nancy Lanza was "psychotic."

But from CNN (yeah I know, but):

"Police Chief Donald Briggs Jr. told reporters that he knew Nancy. [link to articles.cnn.com]

“She was a great person who would do anything for you, a heart of gold. She was just a real, real nice, nice person,” he said, according to the Union Leader newspaper of Manchester.

Nancy Lanza was a giving, quiet, reserved person who grew up on a farm in New Hampshire with three siblings in a self-reliant family, Marsha Lanza said."