Here is an interesting link with regards to parasitic infections. 9% of Americans are infected with Toxoplasma gondii, a cat parasite. Often harmless, it is warned against during pregnancy. But studies have shown that persons with Toxoplasma are twice as likely to develop schizophrenia than non-carriers.
A while ago, I reported on the interesting finding that mice infected with Toxoplasma lost their fear of cats, therefore improving their chance of being eaten by a cat, thereby infecting the cat in turn with Toxoplasma. Some parasite can release targeted chemicals to produce such effects. It is no wonder that their presence can cause altered mental states.
It is quite likely that Toxoplasma is not the only infection that can influence our mental state. That is why Dr. Weeks says: “Before you take anti-psychotic medications for the rest of your life, ask your doctor to determine first whether or not you are infected with something!”
See the whole article here: http://weeksmd.com/?p=4611