Tom ran a segment about the study done showing many suicides related to Toxoplasma gondii from cats.
Here's just a segment from the article at the link below that debunks the study:
Never mind the fact that cat feces contaminated with Toxoplasma gondii don’t even begin shedding the parasite until at least 24 hours after they leave the cat’s body -- so if you clean the litter box daily, you don’t have to worry about being exposed.
Never mind that even cats infected with T. gondii only shed the parasite for a few days in their entire lives. And please, never mind that if your cat lives indoors only, the chance that she’s infected is infinitesimally small.