• Home  / 
  • Featured
  •  /  Does A Brain Parasite Cause Road Rage?

Does A Brain Parasite Cause Road Rage?

A connection between the parasite Toxoplasma gondii and outbursts of anger has been found.

People with intermittent explosive disorder (manifest as outbursts of anger) are twice as likely to have been infected with the parasite, according to a new study.

  1. gondii is a parasitic micro-sized animal, and it is capable of infecting virtually all warm-blooded animals. In humans, most cases are asymptomatic. although with some there are mild-fever like symptoms. The disease can be dangerous in those who are immunocompromised, where the disease toxoplasmosis can develop.

The parasite is spread via the feces of cats. People become infected by unintentionally ingesting the microscopic oocysts (parasite eggs). It is thought, in the developed world, up to one third of people carry the parasite. The parasite lurks in the brain.

The link with changes to personality and the display of anger is something new. This finding has come after researchers examined 358 adults to see if their levels of impulsiveness and aggression were linked to infection with the parasite. Various tests were conducted looking at different emotions. The test results were then correlated against blood samples, to see if the parasite was present.

The findings showed people who tested positive for a past exposure to the parasite scored far higher on scales of aggression compared with those who were not carrying the parasite (although not everyone who tested positive for toxoplasmosis had any aggression issues). If the parasite is the cause, then the most likely explanation is an alteration to brain chemistry caused by the infection. Scientific American reports that earlier studies have linked toxoplasmosis to schizophrenia, bipolar disorder, impulsivity and suicidal behavior.

Importantly, the results only show an association. It is not known whether toxoplasma cause the aggressive behavioural pattern or if someone with the behavioural pattern is more likely to catch toxoplasma infection.

The lead scientists behind the study, Dr Royce Lee, who is employed by the University of Chicago, told The Guardian what sparks the psychiatric condition of intermittent explosive disorder:

“The kind of triggers are usually social provocations. In the workplace it could be some kind of interpersonal frustration, on the road it could be getting cut up.”

The findings are published in the Journal of Clinical Psychiatry. The research paper is titled “Toxoplasma gondii Infection: Relationship With Aggression in Psychiatric Subjects.”

About the author

Tim Sandle

Dr. Tim Sandle is a chartered biologist and holds a first class honours degree in Applied Biology; a Masters degree in education; and has a doctorate from Keele University.