Road rage disorder linked to brain parasite

People infected with a common brain parasite transmitted through the feces of infected cats, undercooked meat or contaminated water may be at increased risk of getting involved in road rage, new research suggests.

In a study involving 358 adults, the researchers found that toxoplasmosis, a relatively harmless parasitic infection carried by an estimated 30 percent of all humans, is associated with intermittent explosive disorder and increased aggression.

"Our work suggests that latent infection with the toxoplasma gondii parasite may change brain chemistry in a fashion that increases the risk of aggressive behaviour," said senior study author Emil Coccaro, professor at University of Chicago.

"However, we do not know if this relationship is causal, and not everyone that tests positive for toxoplasmosis will have aggression issues," Coccaro added.

The findings were published in the Journal of Clinical Psychiatry.

Transmitted through the feces of infected cats, undercooked meat or contaminated water, toxoplasmosis is typically latent and harmless for healthy adults.

However, it is known to reside in brain tissue, and has been linked to several psychiatric diseases.

Examining 358 adults from the US, the researchers found that those with higher on scores on anger and aggression were more than twice as likely to test positive for toxoplasmosis exposure.

"Correlation is not causation, and this is definitely not a sign that people should get rid of their cats," study co-author Royce Lee, associate professor of psychiatry and behavioural neuroscience at University of Chicago, pointed out.

"We don't yet understand the mechanisms involved--it could be an 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 meat," Lee noted.