Robert Wenzel, on his excellent Economic Policy Journal blog has a post reporting that Newtown, CT shooter Adam Lanza was on Fanapt, an anti-psychotic medication with some very alarming side-effects;

Fanapt may cause aggressive/violent behavior (frequent)...Psychiatric side effects including restlessness, aggression, and delusion have been reported frequently. Hostility, decreased libido, paranoia, anorgasmia, confusional state, mania, catatonia, mood swings, panic attack, obsessive-compulsive disorder, bulemia nervosa, delirium, polydipsia, psychogenic impulse control disorder, and major depression have been reported infrequently...

Scanning both WebMD and wikipedia for Fanapt side effects reveals that great pains have been taken, apparently, to make information on the "frequent", "severe" psychotic side-effects difficult to find. WebMD has them, but on a difficult-to-find secondary page). The wikipedia entry dispenses with such chicanery, however - it simply does not mention them. 

Draw your own conclusions.