This may sound outrageous at first. The suggestion that mental illness, currently an epidemic in modern society, can be caused by bacteria and pathogens like a common cold is nearly unheard of.
Getting schizophrenia from a cat? Developing anorexia after getting strep throat, or even depression from bacteria in your stomach?
While it seems strange, there are some truths to be found. For example, before the discovery of penicillin curing syphilis, a large quantity of people in mental institutions were admitted for 'delusions, hallucinations, and hearing voices'. This was called psychosis and many people died from it. However, when penicillin was found to cure syphilis, the amount of these patients dropped dramatically. The conclusion? That specific form of psychosis was a late stage of syphilis, and thus, when syphilis was cured, the psychosis was as well.
In another example, cats are known carriers of zoonotic pathogens. Most people simply aren't affected by it. In 1871, England had its first cat show, and that same year, the number of people who owned house cats skyrocketed. Cats were no longer just outside animals meant to catch rats and other vermin, they became our pets. At the same time, rates of schizophrenia also skyrocketed.
Cats carry a type of bacteria that is present in many four-legged mammals, but only reproduces in felines. Most people are not affected by it, but according to some studies, it has been thought to cause sickness and, yes, even schizophrenia.
Moving ahead, untreated cases of strep throat in some children has shown sudden onslaughts of OCD and anorexia. Healthy children who, only days after their sore throats have healed, suddenly become obsessed with washing their hands or exercising. In 1998, a pediatrician named Susan Swedo laid out the theoretical paper of PANDAS, or, pediatric autoimmune neuropsychiatric disorders associated with streptococcal infections. PANDAS encompasses any sort of OCD, Tourettes, anorexia, anxiety, etc., that has appeared in children after they have sore throats/strep throat.
Most of the cases that Harriet A. Washington give us are usually highly isolated cases, and, in my opinion, very theoretical. I still have a hard time believing cats can cause schizophrenia or that gut bacteria can cause depression. It's an interesting theory, and one that should be researched more in the following years. It's rather new; Washington started gathering research in the late 1990's, and only a few other scientists and doctors have furthered the research.
There's something to be said about it, for sure. One example was the case of the flu; severe cases of the flu can cause delusions and hallucinations in the late stages. She brought up the comparison in that, if we took the knowledge of the flu away, delusions and hallucinations of that sort are most certainly a 'mental illness'. But with the flu, we see it as fairly normal and a common occurrence.
So, when do we draw the line? Between bacterial infections and infections of the mind? Or, at least in some cases, are they one and the same?