Toxoplasmosis, sometimes referred to as simply “Toxo,” is an illness that can result from contact with a single-celled parasite called Toxoplasma gondii. The parasite is found is most places throughout the world and the CDC
estimates that approximately 60 million people in the US are infected with the parasite. Most of them will not become ill however since the immune system is very good at keeping the parasite in check. Exposure to toxo can come from consuming or being in contact with contaminated meat. The most common place the parasite is found in the US is in the feces of cats. With so many homes having cats as pets, it can present a danger for pregnant women or those with compromised immune systems.
New information from a recently conducted study
suggests it might be more dangerous than previously thought. A team of scientists from the University of Chicago looked at 358 adult subjects and found that those with a psychiatric disorder involving recurrent bouts of extreme, impulsive anger, like some forms of PTSD and individuals who have poor impulse control and cannot manage their anger are more than twice as likely to have been exposed to the toxoplasma gondii than people without any psychiatric disorders.
In a press release
from the university, senior study author Emil Coccaro, MD, the Ellen. C. Manning Professor and Chair of Psychiatry and Behavioral Neuroscience said, “Our work suggests that latent infection with the toxoplasma gondii parasite may change brain chemistry in a fashion that increases the risk of aggressive behavior. However, we do not know if this relationship is causal, and not everyone that tests positive for toxoplasmosis will have aggression issues.” Dr Coccaro stressed the need for further study of the relationship of toxo to aggression.
Intermittent explosive disorder (IED) is the illness the study suggests could be related to toxo. According to the National Institute of Mental Health
as many as 16 million Americans suffer with IED, and this is more than the number of patients with schizophrenia and bipolar disorder combined. While close to 82% of those diagnosed with IED also had depression or anxiety, very few, less than a third, of patients received treatment for the aggression and anger they experienced.
In the study, the participants were divided into three groups. One third were people diagnosed with IED, one third with no psychiatric conditions and one third with some form of mental illness, but not IED.
The results of the study showed
in the IED group, the rate of exposure to toxo was 22% compared to the healthy group where the rate was only 9%. The third group, those with a mental disorder other than IED had a rate of 16%, making the IED diagnosed group the most likely by more than double that of healthy individuals to have been affected by the parasite. More significantly, in every group, those who tested positive for toxo scored higher in the areas of anger, impulsivity and aggression.
While the study showed a correlation between toxo and inappropriate aggression and anger, the study team was quick to point out that mechanism isn’t clear. In an interview with CBS News
Coccaro explained, "Anything that gets in the brain that can impact neural chemistry can have behavioral effects.”
Take a look at the video below to learn more about the study and the parasite that might be related to aggression. The team at the University of Chicago hopes that if causation can be determined it could lead to treatments for IED, such as treating the underlying infection.