Toxoplasmosis linked to schizophrenia risk

[HA]

Toxoplasmosis linked to schizophrenia risk
Tue May 24, 2005 02:01 PM ET

NEW YORK (Reuters Health) - Pregnant women with high levels of antibodies to a common parasite, Toxoplasma gondii, run the risk having a child who will develop schizophrenia or a schizophrenia-like disorder in adulthood, new research suggests.
Infection with Toxoplasma is widespread. People can pick it up quite easily, especially when cats are around because the animals frequently harbor the parasite.

A pregnant woman who contracts toxoplasmosis can pass the parasite on to her unborn baby, with serious consequences. On the other hand, a woman who has had the infection and has become immune cannot pass the organism on to her baby during pregnancy.

If the infection is spotted, pregnant women can be treated with antiparasitic drugs to lower the risk to their babies.

"Given that toxoplasmosis is a preventable infection," say the authors of the new study, "the findings, if replicated, may have implications for reducing the incidence of schizophrenia."

As reported in the American Journal of Psychiatry, Dr. Alan S. Brown, from the New York State Psychiatric Institute in New York, and colleagues, evaluated the link between maternal exposure to Toxoplasma and schizophrenia risk in a large group of people born between 1959 and 1967.

They identified 63 people who developed schizophrenia and compared them with 123 similar "controls" without schizophrenia. The researchers tested stored blood samples, obtained from the mothers while they were pregnant, for Toxoplasma antibodies. Antibody levels were classified as negative, moderate, or high.

A high Toxoplasma antibody level, indicating heavy infection around the time of pregnancy, more than doubled the likelihood of schizophrenia in the adult offspring. By contrast, moderate levels seemed to have no effect on the risk.

"The findings may be explained by reactivated infection or an effect of the antibody on the developing fetus," the researchers conclude.

"These findings add to a growing literature suggesting a relationship between in utero exposure to infectious agents that are known to disrupt fetal brain development and the risk of adult schizophrenia," they add.

SOURCE: American Journal of Psychiatry, April 2005

 

[just mary]

HeartArt,

Thanks for the information, it was interesting. And I do appreciate it. I also seem to recall a study relating mothers who caught the flu and a higher incidence of schizophrenia among their children.

But as someone who is thinking of conceiving, the inundation of things that can negatively affect your offspring during pregnancy is unreal. Everywhere I turn I'm being told what could be bad for my unborn baby, it's getting to the point that I'll be afraid to eat if and when I do get pregnant. And even though I bike to and from work (which is supposedly healthy) I think of all the exhaust I'm inhaling. You're even told how you should sleep. And I know I drink too much now but I didn't drink at all when I was pregnant but apparently what you do in the three months before conceiving can also have an effect on your baby. I read that in a Discover magazine article (either late 2003 or 2004), it was very interesting.

But I hope my last paragraph didn't sound negative, I do appreciate the information, it's just something I've been feeling/noticing more so lately. It just feels so overwheliming.

Thanks,

 

[HA]

Hi Mary!

I think it's important, as you say, to not become too hypervigilant about all of the things that "could" cause problems. On the other hand it is important to be knowledgable about risks. I personally would not be cleaning the litter box or, if I had no choice, taking extra precautions like wearing mask and gloves. Just knowing that there is such a thing as *toxoplasmosis*, weather it was related to schizophrenia or not would be enough cause for concern for me.

There have recently been outbreaks of Rubella in ON so people who are pregnant or planning should most definitely be aware of this.

One concern that you should be very aware of, Mary, is the risk of alcohol to the developing fetus. I did a course on the The Developing Brain and we looked extensively at alcohol. It is known for sure that alcohol causes damage to the fetus, even through the male sperm. Studies show what the largest quantity of alcohol is that will cause damage but it is not known what the least amount of alcohol is that can cause harm. We do not know, for example, if one drink at a particular point in development may be just as harmful as heavy drinking. This is why it is important to be alcohol free during pregancy.

Alcohol is the leading known teratogen. Alcohol ingested during pregnancy can produce a wide spectrum of defects, ranging from spontaneous abortion to severe behavioral effects without physical anomalies. The risk of spontaneous abortion increases about twofold, particularly with heavy drinking (> 3 drinks/day). Decreased birth weight is the most reliable indicator of prenatal alcohol exposure, with the average birth weight of such newborns estimated to be about 2.0 kg (4.4 lb); the average birth weight for all newborns at term is about 3.3 kg (7.3 lb).

The incidence of fetal alcohol syndrome, one of the major consequences of drinking during pregnancy, is about 2.2 in 1000 live births. The syndrome includes growth retardation before or after birth; facial anomalies (eg, shortened palpebral fissures); joint contractures; cardiovascular defects; and CNS dysfunction, including microcephaly, varying degrees of mental retardation, and abnormal neurobehavioral development. The syndrome is a leading known cause of mental retardation; its incidence exceeds that of Down syndrome and cerebral palsy. In general, the extent of mental retardation is positively related to the severity of dysmorphogenesis. Microcephaly, a common feature, probably results from the overall decrease in brain growth. Perinatal mortality may occur, and the newborn may fail to thrive. The critical volume of ingested alcohol that results in this syndrome is unknown. In one study, the incidence of abnormalities did not increase until > 45 mL/day of alcohol (3 drinks/day) was ingested (see also Fetal Alcohol Syndrome under Metabolic Problems in the Newborn in Ch. 260).

from The Trusted Provider of Medical Information since 1899

Here is a link to other drugs that cause birth defects.
http://www.kumc.edu/gec/support/teratogen.html

These are the things that you need to be concerned about more so than how you sleep.

 

[just mary]

Hi,

Do I sound like I'm protesting too much when I say I didn't drink while pregnant? I truly didn't, it was the easiest thing to do. I knew within a week that I had become pregnant (which some may find hard to believe but it was something I "just knew", my body felt completely different), at which point all alcohol became undesirable. I just stopped.

I thought to myself, "if I have a beer, my baby has a beer, she can't leave or say no, she's completely dependent on me, she doesn't just want me, she needs me". And it worked. I even remember having to go out one evening right after we found out that she was dying (sounds stupid but it was for the wedding of a very close friend of my husband's) and I went up to get drinks for my husband and I. Ken had to test mt drink to see if I had put anything in it, he did, there was nothing. I wasn't even able to drink at the point since I couldn't imagine getting her "drunk" with so little time left. Just so you know, I don't blame Ken, he's never been pregnant (at least I hope not) and he was just going on my pre-pregnancy behaviour.

Thanks HeartArt.

 

[David Baxter PhD]

I do think being careful with common bacteria, parasites, viruses, and environmental toxins, as well as everything the mom eats and drinks during pregnancy makes sense, and I'm also happy to see the medical research world putting effort into examining every potential causative factor of mental illnesses.

On the other hand I worry a little about adding more to the burden of guilt felt by mothers who have had children that eventually develop these conditions or disorders. I do think it's important to keep it in perspective: An illness like schizophrenia affects ony a small percentage (thankfully) of the babies born every year. Many more babies than the number exposed to certain parasites, or the 'flu, or measles, or even alcohol grow up to be perfectly normal.

How to account for those prenatal infants who survive such exposure intact and those who develop schizophrenia or some other health or mental health condition is going to be the real challenge in sorting out causative factors. One thing that is clear to me is that it almost certainly will not turn out to be a single factor, but rather a certain combination of factors.

As a somewhat silly example, drinking does not cause fatal traffic accidents. In otder for drinking to lead to a fatal traffic accident, there must be a combination of factors occurring together at the same time and place in order for that fatal accident to result, the first of which of course must be that the person who has been drinking enters a vehicle as the driver.

 

[HA]

Mary,

No, I don't think it sounds like you are protesting at all. Just discussing and sharing. I hope you didn't take this as a finger wagging, Mary. I just thought this information was important to share. Moms should rest assured, that if they have discovered their pregnancy, after indulging in cocktails, that it is not likely that any harm was done. It is the heavy or binge drinking during pregnancy that is the known risk factor.

Dr Baxter, makes a very good point about mothers and guilt around pregnancy issues when there have been complications. Many factors do come into play and if we look at schizophrenia alone, even just the genetic factor is a result of probably 10-20 genes which are expressed in a multitude of combinations, plus the possiblity of other numerous factors.