Forget guns, this is the real problem.
http://www.huffingtonpost.com/2012/12/16/i-am-adam-lanzas-mother-mental-illness-conversation_n_2311009.html?icid=maing-grid7
http://www.cnn.com/2012/12/14/world/americas/analysis-connecticut-shooting-mann/index.html?iref=obinsite
Though I wouldn't exactly consider it "off the agenda," as it is very much discussed and debated here.