A new study by the University of Chicago Medical Center states that there is a definitive connection between Intermittent Explosive Disorder and exposure to the common toxoplasma gondii parasite, which is generally found in cat feces and undercooked meat. The individuals that are affected by psychiatric disorders that involve recurrent episodes of unsuppressed anger and impulsive road rage are more likely to have been exposed to this parasite infection.
According to the team of researchers, there it is twice as much possibility for the people who suffer from road rage to be exposed to a common parasite than any healthier individual who hasn’t been diagnosed with any psychiatric problem or disease. The study encompassed 358 subjects, and the researchers found that in almost 30% of the subjects there was a definitive infestation of a relatively harmless parasitic infection, known as toxoplasmosis. This infection-causing parasite can be associated with enhanced aggression, anger, and intermittent explosive disorders.
According to the senior author of the study, Ellen Manning, Professor of Psychiatry and Behavioral Neuroscience at the University of Chicago, “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.” Manning also expressed the need for further studies by saying, “However, we do not know if this relationship is causal, and not everyone that tests positive for toxoplasmosis will have aggression issues.”
The Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition describes intermittent explosive disorder (IED) as “A recurrent, impulsive, problematic outburst of verbal or physical aggression that are disproportionate to the situations that trigger them.” IED is believed to have affected at least 16 million Americans up until last year, and the numbers are just rising. The recurrence of this disease is much more common than that of bipolar disease and Schizophrenia if combined.
The research team’s objective is to find a possible cure and diagnostic process for impulsive anger and IED. For this, they have observed and studied the phenomenon of toxoplasmosis and its connection to road rage. Although it is a latent infection, which is harmless for healthy adults, it can reside in brain tissues and can lead to harmful psychotic diseases such as schizophrenia, suicidal behavior, and bipolar disorder. The search team found out that the diagnosed group is twice as likely to be diagnosed than a patient of toxoplasmosis is.
Across all the subjects, one thing that remained constant is the high score each individual scored on the anger and aggression levels. The team also found a direct connection between the toxoplasmosis and enhanced impulsive behavior, but when they adjusted the aggression scores in conjunction with that, the connection became weak and insignificant. Although there is a direct link established between toxoplasmosis and aggression, scientists still haven’t been able to identify if the toxoplasmosis infection can cause increased aggression or not.
The study’s co-author Royce Lee, MD, Associate Professor of Psychiatry and Behavioral Neuroscience at the University of Chicago, said in a statement, “Correlation is not causation, and this is definitely not a sign that people should get rid of their cats. 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. Our study signals the need for more research and more evidence in humans.”