Is there a connection between cats and schizophrenia?
by J. Lawrence

One has to wonder why Dr. E Fuller Torrey has, for thirty years, continued to promote his theory that cats cause schizophrenia and other psychiatric illness. He claims to simply be a believer and on a scientific quest, but I don't buy it.

My opinion, after doing some research on the subject, is fairly simple on the whys: it makes good headlines. It's controversial, and the media loves something so simple, so black and white: schizophrenia is not a complex spectrum of disorders, and its cause is not found in contemporary theory - that the root of the disease is likely a complex interaction of genetics and environment. Torrey can make a wild claim, backed up by no evidence, and the media runs with it: cats cause schizophrenia.

What leads me to this opinion is a piece of his "research" that is conveniently ignored in media stories: the handful of studies that do show a higher level of antibodies to Toxoplasma gondii in schizophrenics also show higher levels of herpes and cytomegalovirus.

Saying that herpes causes schizophrenia isn't as fun as blaming it on cats. It's also safer to blame cats, because they don't have much of a voice and aren't likely to show up at Torrey's house with protest signs.

For 30 years, it's been his obsession, despite his protests that he loves cats. And for 30 years, Torrey and collaborator, virologist Robert Yolken, have tried to prove infectious agents, notably viruses during pregnancy, cause mental illness.

They continue to come up with very little. The best they can do is point to studies that show untreated schizophrenics have a higher incidence of antibodies to Toxoplasma gondii than schizophrenics taking medication, or persons without schizophrenia.

The same studies show similar rates of herpes virus and cytomegalovirus.

Other studies show schizophrenics more likely to be born in winter or spring, though Torrey's own study in Australia showed no connection. More studies have shown schizophrenia to appear more often in urban areas, as well as in crowded households.

These factors helped convince Torrey that an infectious agent played a key role in the development of schizophrenia.

In reality, despite the claims of advertisements on TV, or flippant claims by psychiatrists, nobody knows what causes mental illness. It's called biological, but the evidence for that remains as elusive as evidence showing viruses cause the illness. E Fuller Torrey gets more press by being the kook who says cats cause schizophrenia. And book deals.

His first clue, he has said, was the realization that cats were introduced into modern society as pets in the late nineteenth century, the same time that schizophrenia and bipolar disorder went from being rare diseases to common ones. He believed that cats were the culprit.

Since 1953, 19 studies of Toxoplasma gondii antibodies in persons with schizophrenia and other severe psychiatric disorders have been published. Of those, 11 reported a statistically significant difference between the mentally ill persons and controls. In other words, slightly more than half said there *were* differences and the others said there weren't. That's hardly convincing evidence.

Torrey has nearly 400 brains stored in 55 freezers in his "Brain Bank," part of the Stanley Foundation. Torrey examined 51 postmortem brains and found herpes virus 6 in two of them, but no Toxoplasma gondii at all.

Key points:

--Almost half the studies that have been done have NOT shown any correlation between mental illness and the presence of Toxoplasma gondii antibodies

--In studying 51 brains, he found no Toxoplasma gondii

--Torrey has been researching this for thirty years, and has yet to provide any evidence of cause and effect

--The studies have also shown similar incidences of herpes and cytomegalovirus in persons with schizophrenia, but these results have largely been ignored...because they don't fit in with blaming cats

--The studies showing a difference in antibodies also show that schizophrenics taking antipsychotic drugs have a lower rate of antibodies, leading
Torrey to make claims that this class of drugs may actually fight viral infection. If there were any evidence of that, wouldn't the drug companies be rushing to find another market for their antipsychotic medications? If these drugs had any effect on viruses, the drug companies could make billions by remarketing the drugs.

--No mention of other societies (ancient Egypt) that have had cats, and whether or not they had psychotic disorders.

--A least one-third of the world may have contracted toxoplasmosis

--A study in the 90s of Czech soldiers and students (funded by Torrey's Stanley Foundation) claimed toxomplasmosis made men more aggressive, jealous and suspicious, while it raised the intelligence of women and apparently caused them to spend more on clothes and engage in promiscuous behavior

The bottom line is this-
There is no evidence that cats will make you mentally ill, and studies have in fact shown the reverse is true. Cats can have a very beneficial effect for mentally ill and depressed people! So go adopt a cat (or two) today!


Good article on toxoplasmosis, says it's usually caused by undercooked meat:

NY Times Magazine: (date unknown, but appears to be about 2000-2001)

Medline, medical journal abstracts:

Birth season study: