I've mentioned before the possible mind altering effect of toxoplasma, the bug that is carried by cats. (The suggestion being that, just as infected rats have been shown to have a much reduced fear of cats, people with the bug in their brains might also take more risks in life.)
While wandering around the Web this week, I was very surprised to find that there have also been studies to see if there is a link with full blown schziophrenia. See this CDC study here. It's a bit of a worry. The summary:
"Since 1953, a total of 19 studies of T. gondii antibodies in persons with schizophrenia and other severe psychiatric disorders and in controls have been reported; 18 reported a higher percentage of antibodies in the affected persons; in 11 studies the difference was statistically significant. Two other studies found that exposure to cats in childhood was a risk factor for the development of schizophrenia."
I have read before that the rate of toxoplasma infection (as shown by blood studies) varies from country to country a great. France has a very high rate (around 80% !!,) believed to be from a fondness for eating rare meat. So, one would presume if there was any connection between toxoplasma and schziophrenia, it should up in that country's rates of madness. Seems like it does (although the study is very cautious about this):
"Whether any geographic association exists between the prevalence of toxoplasmosis and the prevalence of schizophrenia is unknown. France, which has a high prevalence of Toxoplasma-infected persons, was reported to have first-admission rates for schizophrenia approximately 50% higher than those in England (41). Ireland also has a high rate of Toxoplasma-infected persons in rural areas (42), confirmed by the high rate of infection in hospital personnel in our own study. "
Is there clear evidence that toxoplasma infection can cause schziophrenia like symptoms. Yep:
"Some cases of acute toxoplasmosis in adults are associated with psychiatric symptoms such as delusions and hallucinations. A review of 114 cases of acquired toxoplasmosis noted that “psychiatric disturbances were very frequent” in 24 of the case-patients (10). Case reports describe a 22-year-old woman who exhibited paranoid and bizarre delusions (“she said she had no veins in her arms and legs”), disorganized speech, and flattened affect; a 32-year-old woman who had auditory and visual hallucinations; and a 34-year-old woman who experienced auditory hallucinations and a thought disorder (11). Schizophrenia was first diagnosed in all three patients, but later neurologic symptoms developed, which led to the correct diagnosis of Toxoplasma encephalitis. Psychiatric manifestations of T. gondii are also prominent in immunocompromised persons with AIDS in whom latent infections have become reactivated."
So should cats be seen as a risk factor for schziophrenia? Seems a pretty good case exists:
"Epidemiologically, two studies have reported that adults who have schizophrenia or bipolar disorder had a greater exposure to cats in childhood. In one study, 84 (51%) of the 165 affected versus 65 (38%) of the 165 matched controls had owned a house cat in childhood (p = 0.02) (39). In the other study, 136 (52%) of the 262 affected versus 219 (42%) of the 522 matched controls owned a cat between birth and age 13 (odds ratio 1.53; p <>
Fascinating, hey? And I am very surprised that I had never heard of this before. (The CDC paper is nearly 2 years old now.) Maybe a world wide conspiracy of cat owners is suppressing this news from the MSM.