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Constant Rage and Aggression Could Be Linked to Brain Parasite


Clean the damn litter box, people!

Intermittent explosive disorder (IED) is when people are overcome with anger and lose control of their emotions. This disorder is characterized by hostility, loss of control and recurring aggressive outburst. People with IED can explode into a rage-filled episode with very little provocation or reason. Think: road rage.

But a new study from the University of Chicago has found a link between IED and toxoplasmosis, a parasite commonly associated with cat feces.

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Toxoplasmosis is a generally harmless parasitic infection that’s passed on through the feces of infected cats, or drinking contaminated water or raw goat’s milk, or from raw or undercooked meat. Toxoplasmosis affects around 30 percent of all humans but is normally latent.

“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,” said the study’s lead researcher, Emil Coccaro, MD, in an article on Medical News Today. “However, we do not know if this relationship is causal, and not everyone that tests positive for toxoplasmosis will have aggression issues.”

Previous research has shown that the parasite is found in brain tissue and has been linked to a number of psychiatric conditions including schizophrenia, bipolar disorder, and suicidal behavior. Although most people who have toxoplasmosis are unaware that they have it, it can be very serious if a woman catches it just before or during pregnancy. It’s also not good for people with a weakened immune system, though there are medications to treat it.

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Some ways to avoid getting toxoplasmosis include not touching your hands to your mouth after gardening, cleaning the litter box, not coming into contact with raw or partially cooked meat, not using utensils or cutting boards that weren’t properly cleaned after coming into contact with raw meat, and not eating raw or partly cooked lamb, pork or venison.

For the study, the researchers recruited 358 adult participants from the United States who were evaluated for IED, personality disorder, depression and other psychiatric disorders. Study subjects were rated on traits that included anger, aggression and impulse control.

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Roughly one-third had IED, one-third had some psychiatric disorder that wasn’t IED, and one-third were healthy controls with no psychiatric history.

The researchers found that those with IED were more than twice as likely to test positive for toxoplasmosis exposure (22 percent), while only 9 percent of the healthy group and 16 percent of the psychiatric control group were likely to test positive.

Across all study subjects, toxoplasmosis-positive people scored significantly higher on scores of anger and aggression, suggesting that toxoplasmosis and aggression are strongly linked.

The authors point out that their findings don’t mean that toxoplasmosis causes IED or that people with cats are more likely to have the condition.

“This is definitely not a sign that people should get rid of their cats. It could be increased inflammatory response, direct brain modulation by the parasite, or even reverse causation where aggressive individuals tend to have more cats or eat more undercooked meats,” said the study’s coauthor, Dr. Royce Lee.

There’s no reason to panic. Just wash your hands after cleaning the litter box and before touching your face. It’s really a no-brainer. Plus, I don’t think anybody wants to touch their face after coming into contact with cat poop anyway.

This guest article originally appeared on If You’re Rage-y All The Time, Blame A Brain Parasite (Says Science).

Constant Rage and Aggression Could Be Linked to Brain Parasite

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APA Reference
Guest Author, P. (2018). Constant Rage and Aggression Could Be Linked to Brain Parasite. Psych Central. Retrieved on September 27, 2020, from
Scientifically Reviewed
Last updated: 8 Jul 2018 (Originally: 22 Apr 2016)
Last reviewed: By a member of our scientific advisory board on 8 Jul 2018
Published on Psych All rights reserved.