Posted on 12/07/2006 3:44:09 PM PST by shrinkermd
This week's Forbes has an article penned by Fuller Torrey on "Cats and Schizophrenia." Besides being hard to access the article is short and leaves out some information that tones down the alarming nature of the data. Below is an exerpt of a Corante article that fills the data in.
Carl Zimmer's article begins with data on rats and cats suggesting that rat behavior is indeed changed by toxoplasmosis. He then goes on to discuss the specifics in humans.
"...The Oxford scientists knew that humans can be hosts to Toxoplasma, too. People can become infected by its eggs by handling soil or kitty litter. For most people, the infection causes no harm. Only if a person's immune system is weak does Toxoplasma grow uncontrollably. That's why pregnant women are advised not to handle kitty litter, and why toxoplasmosis is a serious risk for people with AIDS. Otherwise, the parasite lives quietly in people's bodies (and brains). It's estimated that about half of all people on Earth are infected with Toxoplasma.
Given that human and rat brains have a lot of similarities (they share the same basic anatomy and use the same neurotransmitters), a question naturally arose: if Toxoplasma can alter the behavior of a rat, could it alter a human? Obviously, this manipulation would not do the parasite any good as an adaptation, since it's pretty rare for a human to be devoured by a cat. But it could still have an effect.
Some scientists believe that Toxoplasma changes the personality of its human hosts, bringing different shifts to men and women. Parasitologist Jaroslav Flegr of Charles University in Prague administered psychological questionnaires to people infected with Toxoplasma and controls. Those infected, he found, show a small, but statistically significant, tendency to be more self-reproaching and insecure. Paradoxically, infected women, on average, tend to be more outgoing and warmhearted than controls, while infected men tend to be more jealous and suspicious.
It's controversial work, disputed by many. But it attracted the attention of E. Fuller Torrey of the Stanley Medical Research Institute in Bethesda, Maryland. Torrey and his colleagues had noticed some intriguing links between Toxoplasma and schizophrenia. Infection with the parasite has been associated with damage to a certain class of neurons (astrocytes). So has schizophrenia. Pregnant women with high levels of Toxoplasma antibodies in their blood were more likely to give birth to children who would later develop schizophrenia. Torrey lays out more links in this 2003 paper. While none is a smoking gun, they are certainly food for thought. It's conceivable that exposure to Toxoplasma causes subtle changes in most people's personality, but in a small minority, it has more devastating effects.
A year later, Torrey and his colleagues discovered one more fascinating link. They raised human cells in Petri dishes and infected them with Toxoplasma. Then they dosed the cells with a variety of drugs used to treat schizophrenia. Several of the drugs--most notably haloperidol--blocked the growth of the parasite.
So Fuller and the Oxford scientists joined forces to find an answer to the next logical question: can drugs used to treat schizophrenia help a parasite-crazed rat? They now report their results in the Proceedings of the Royal Society of London (press release). They ran the original tests on 49 more rats. Once again, parasitized rats lost their healthy fear of cats. Then the researchers treated the rats with haloperidol and several other anti-psychotic drugs. They found that the drugs made the rats more scared. They also found that the antipsychotics were as effective as pyrimethamine, a drug that is specifically used to eliminate Toxoplasma.
There's plenty left to do to turn these results into a full-blown explanation of parasites and personalities. For example, what is Toxoplasma releasing into brains to manipulate its hosts? And how does that substance give rise to schizophrenia in some humans? And even if the hypothesis does hold up, it would only account for some cases of schizophrenia, while the cause of others would remain undiscovered. But still...the idea that parasites are tinkering with humanity's personality--perhaps even giving rise to cultural diversity--is taking over my head like a bad case of Toxoplasma...
From the behavioral changes described, I'd be willing to wager that the incidence of toxoplasmosis is considerably higher in leftists.
I liked the Courante title better, 'Return of the Body Snatchers,' but that title lends no credibility. But, remember Doc, correlation is not cause.
Either we are equal or we are not. Good people ought to be armed where they will, with wits and guns. NRA KMA Merry Christmas
How would one know if their cat was crazy?
Hey! You can't talk about my listees that way! ;^)
so how do I get this test?
LOL
McPhee rules.
Are you the same person who posted the "Cats with Alzheimer" story a little while ago?
no
That was me.
That's so funny....is it a real toy?
*ahem* It's an ACTION FIGURE. Yes it's real. Want one?
Seems that way.
If it looks like this one.
Sobering. Thankfully, was never around kitty litter long . . .
And, my blood has always been clear of such . . . as best as I can recall. LOL.
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