March 9, 2007

Do Cats Cause Schizophrenia?

Filed under: Evolution and You,Views — Sharon Moalem @ 8:05 am

cat.jpgSo what’s it like to be on the Daily Show? I spoke to Jon both before and just after the segment, and he asked me some pretty insightful questions about the nature of scientific discovery.

Okay, some of the highlights of course was getting to plug one of my favorite diseases hemochromatosis, the one which you can actually rust to death by absorbing too much iron from your diet. It’s amazing to think that this condition may have arisen to protect western Europeans from the Bubonic Plague. And even more amazing is that bloodletting or a blood donation is the treatment of choice for hemochromatosis today. I know it sounds medieval but it’s still the best therapy out there. I should know. I have hemochromatosis.

The other topic that is going to have cat lovers everywhere screaming is a nasty little parasite called Toxoplasma gondii. This parasite also goes by the name of toxoplasmosis or sometimes toxo for short. This is a really fascinating parasite because although it can infect almost every mammal out there (including humans) it needs to make its way to cats if it wants to reproduce sexually. How does it get to cats?

Recent research uncovered some shocking mind control tricks that toxoplasmosis uses. In short, when a mouse or a rat eats infected cat droppings, toxoplasmosis moves to the brain and muscle to set up shop. No one knows exactly how the next part works but it seems that being infected with toxoplasmosis can change the behavior of mice. First off the mice get fat and then they seem to lose their fear of cats, which of course turns them into cat food.

Now where does schizophrenia work into all of this? People with schizophrenia have higher rates of infection with toxoplasmosis. Which doesn’t prove a causality, because the higher rates of infection may also be due to poor hygiene or spending time institutionalized. But the smoking gun for me has to do with toxoplasmosis having the ability to change another animals behavior as in the case of mice. I believe toxoplasmosis may be an added trigger not unlike drug use to make someone who’s already susceptible to schizophrenia all the more likely to get sick.


  1. Thank you so much for talking about hemochromatosis. I learned about it about three years ago when someone very close to me disclosed he had the disease. I started hunting through the internet trying to find information about it and was surprised by how many people have it and don’t know. He and I joke about leeches (we are thinking of naming these prospective pets Fred and Oscar) and blood-letting. I met a fellow on LJ who discovered, in his late 40′s that has it. How did you learn about it?

    It is very treatable, but you and I both know the ultimate conclusion. I understand that there have been new tests developed to check people for hemochromatosis. Do you happen to recall the names of these tests?

    By raising awareness, both you and the Daily Show, have helped to lift the veil on this little discussed disease and will extend lives and help families. I cannot wait to read your book!

    Comment by Karen UNITED STATES — March 9, 2007 @ 3:08 pm

  2. I thought your interview was really funny and informative at the same time, and intrigued me enough to seek you out on the internet, and voila! I am on your blog!

    I always knew cats were bad for us (I cannot be in the same house as a cat – allergies!! Now I will torture all my cat-owning friends with this great (and dangerous) little fact from your book!

    Comment by Yamini UNITED STATES — March 9, 2007 @ 8:35 pm

  3. Hi Dr. Sharon,

    On a related subject of excess iron in the body: nearly everyone, family physician included, instructed my wife to continue to take her prenatal vitamin after giving birth, while having a breast-fed newborn exhibiting symptoms of “colic”. These prenatal vitamins are very high in iron, and a friend suggested the excess iron may cause gastrointestinal reflux disorder (GIRD), which is outwardly similar to colic – the infant is crying continually, sleeps fitfully and is in constant discomfort. My wife stopped the prenatal vitamin, and the “colic” symptoms went away completely, and permanently, in about 8-12 hours, after months of virtually uninterrupted symptoms. Other new parents experiencing “colic” with whom we have shared our story have also experienced success.

    Not much seems to be known about colic vs. GIRD, at least in resources accessible to a layperson — and perhaps to many physicians, since ours recommended continuing the high-iron supplement and was surprised at our success when we did the opposite. As well, many infant formulas are iron-fortified, and most websites also seemed to advise high (that is, supplemented) iron content in the infant’s diet.

    I must admit I have not yet read your book, my introduction to the material was via the Daily Show! Your interest in hemochromatosis reminded me of this probably unrelated but perhaps interesting issue of iron in the body.

    Comment by M. Kahn CANADA — March 10, 2007 @ 7:55 am

  4. Wow, so if I fatten up all of a sudden and start playing dead in front of cats, I should be worried? Just kidding. Great stuff. I’m definitely going to have to go out and get the book.

    Comment by Jason UNITED STATES — March 10, 2007 @ 9:51 am

  5. Loved seeing you on the Daily Show. My Dad had hemochromatosis (he died over 30 years ago from pancreatic cancer). I read somewhere that everyone who has hemochromatosis is related, so you must be my long lost cousin! This seems unlikely, since I’m Scottish/Welsh/German from California.

    Anyway, I’ll have to read your book. Nice job on the show the other night. All the doctors I’ve ever seen over the years have always been kind of wowed that my Dad had this malady. It’s as if they’ve only read about it in text books.

    Comment by jentaps UNITED STATES — March 11, 2007 @ 1:22 am

  6. I discovered you through The Daily Show. I’m no scientist, but I try to keep track of how people think about whatever it is we call mental illness. It has political implications: in recent world history, for instance, political dissidents and homosexuals have been considered mentally ill—and therefore subject to involuntary “treatment.” Your idea about schizophrenia is fascinating. Even if it proves true, though, I think Dr. Thomas Szasz should be taken seriously for his broader point about the relationship between the psychiatric profession and the state.

    Comment by Brian Sorgatz UNITED STATES — March 11, 2007 @ 5:45 pm

  7. Hubby & I saw you on The Daily Show and are now very interested in reading your book. Fascinating stuff! Makes me wish I could go back to college and change careers.

    Good luck with your endeavors!

    Comment by Jessika UNITED STATES — March 11, 2007 @ 7:41 pm

  8. fascinating. i am a 31-year old female who was diagnosed with hemochromatosis last year. unfortunately, a great uncle died and that’s how we found about it. me and three uncles have the condition – no other females -lucky me.

    this is very interesting stuff. thanks for spreading the word.

    Comment by c jones UNITED STATES — March 14, 2007 @ 1:09 pm

  9. A question which occurs to me on the subject of toxoplasmosis:

    Cats are well known for ‘playing’ with mice. If the mouse runs then they grab it. If it doesn’t they prod it and watch.
    Could the cat be testing the mouse to see if it is afraid?
    If the cat can judge whether a mouse if infected then what would be the best action for the cat to take? If afraid=uninfected then eat it? If unafraid=infected then cull it but don’t eat it?

    BSE seemed especially dangerous to big cats in zoos. Could cattle harbour BSE as a mechanism to keep their predators under control?

    Comment by Oska AUSTRALIA — June 6, 2007 @ 8:50 am

RSS feed for comments on this post. TrackBack URI

Leave a comment

It sounds like SK2 has recently been updated on this blog. But not fully configured. You MUST visit Spam Karma's admin page at least once before letting it filter your comments (chaos may ensue otherwise).

Powered by WordPress

FireStats iconPowered by FireStats