A few years back, I watched a neighborhood woman slowly transform into the Crazy Cat Lady. It began with a couple strays she took in from the yard, and within the course of maybe 18 months evolved into eleven indoor cats and uncountable feral felines for which she left bowls of food and water on her porch. She stopped leaving her house except to go to Barnes and Starbucks and of course the pet supply store.

All of this frightened me. My neighbor had been a high-powered executive at an accounting firm. How had she transformed into a reclusive, slipper-footed bookworm, often seen on her porch wearing her pajamas well into the afternoon? (Although I must admit, she did seem happier this way.) Some scientists believe we’ve been looking at the problem in reverse; it’s not that crazy people like and understand cats; it’s that cats make us crazy!

Before smacking your friend the cat lover over the head with this issue hollering how you told her so, let’s be more specific. Most people have heard that pregnant women shouldn’t clean the litter box because cat feces is a source of Toxoplasma gondii, a parasite causing a disease known as toxoplasmosis. If contracted during development in the womb, this disease can result in blindness and mental retardation. This has been known for a long time. But recently, researchers are testing theories about a possible link between Toxoplasma gondii and schizophrenia.

Your DNA contains things called “endogenous retroviruses.” These are remnants of ancestral viral infection, and are considered mostly harmless, though they are suspected of involvement in some autoimmune diseases, especially multiple sclerosis and some cancers. It’s now theorized by some researchers that Toxoplasma triggers one of these retroviruses, which in turn begins to slowly damage hippocampus area of the brain. The damage doesn’t evidence until the brain stops growing in adolescence. (Most schizophrenia develops between ages 16 and 30.)

One study indicated a higher incidence of cat ownership among the parents of children who developed schizophrenia (51 percent) versus those who did not (38 percent). Schizophrenia was relatively rare in Europe until the late 19th century; this is when the cat became a trendy pet, much like the purse dogs made popular today by Paris Hilton and her ilk. Similar trends have been tracked in the States. Also, seasonal correlations are observable--a statistically relevant higher number of individuals born in the winter or spring months develop schizophrenia. Seasonal correlations are considered one telltale sign of infectious agents. Bleeding from the eyes is another.

Granted this “evidence” is mostly circumstantial and certainly based on conjecture, like observing that people eat more ice cream in the summer and homicide goes up in the summer and then concluding that consumption of ice cream sparks the desire to kill people. (Although a lack of ice cream has sparked in me a desire to kill people.)

But it is a phenomenon worth studying and researching if only for the larger ramifications. The search for physiological or biological bases of mental illness was largely abandoned in the 1950s, as Freudian psychoanalysis fully permeated the American psychiatric profession. In the 1980s the pendulum swung the other way, and genetic explanations to mental illness were being sought. It was believed that a “schizophrenia gene” would be identified, solving the mystery.

There were patterns that genetics could not explain, however, such as higher incidents of schizophrenia in urban areas and other external influences. Some thirty years ago it was proposed that most cases of schizophrenia and bipolar disorder were perhaps caused by infectious diseases. This new approach was conceived by E. Fuller Torrey, a psychiatry professor at the Uniformed Services University of Health Science. Though many research doctors, on many days himself included, view his idea with extreme skepticism, he has found collaborators, chief among them Johns Hopkins virologist Robert Yolken.

Their exploration led them serendipitously to a cache of 53,000 frozen blood samples originally taken from pregnant women during the 1950s as part of an anti-polio campaign. They tracked down the children of these women and found about 100 had developed schizophrenia. They then tested the blood samples of the mothers for infectious diseases. Blood levels of antibodies to toxoplasmosis in mothers whose children who had become schizophrenic at a rate 4.5 times greater than in the other mothers. There was an even higher incidence – 7.5 times greater – for antibodies to herpes simplex two.

As a result of this finding, Torrey and Yolken plan to treat one test group of schizophrenics with an antibiotic that kills Toxoplasma, and another group with an anti-viral drug used against the herpes virus. This is a completely new approach to psychopharmacology. If it proves fruitful, perhaps the treatment of other mental illnesses, such as Parkinson’s or Alzheimer’s could also be treated with antibiotics or antivirals.

In the meantime, don’t toss out your housecat. Unless of course you want to. To put all this in perspective, Toxoplasma gondii is typically found in the feces of only about one percent of house cats. The parasite is killed by most people’s immune systems before it causes the disease toxoplasmosis. My Crazy Cat Lady neighbor was always a bit of a recluse, really. But don’t be surprised if after they confirm that cats cause craziness, they discover that purse-sized dogs cause dumbness.