Individuals with a psychiatric disorder involving recurrent bouts of extreme, impulsive anger — road rage, for example — are more than twice as likely to have been exposed to a common parasite than healthy individuals with no psychiatric diagnosis.
In a study involving 358 adult subjects, 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.