Feeling angry? Your cat’s poop might be to blame

If you own a cat, here’s even more of a reason to wash your hands after cleaning out the litter box. A new study suggests that people prone to aggressive behavior might be under the influence of toxoplasmosis, a foodborne illness caused by a parasite found in cat litter and undercooked meat.

Researchers found that people diagnosed with intermittent explosive disorder (IED) are more than twice as likely to carry Toxoplasma gondii, the parasite that causes toxoplasmosis. They recruited 358 adults for this study, recently published in the Journal of Clinical Psychiatry, and split them into three groups — people with intermittent explosive disorder, people with a psychiatric disorder other than IED and healthy individuals with no mental illness.

Twenty-two percent of people with IED tested positive for toxoplasmosis exposure. That compared to just 9 percent of the healthy control group, the study said.

According to the National Institute of Mental Health, intermittent explosive behavior, marked by episodes of unwarranted anger, affects as many as 7.3 percent of adults — 11.5-16 million Americans — in their lifetimes. People with IED may attack others and their possessions, causing bodily injury and property damage.

Toxoplasmosis is considered to be a leading cause of death attributed to foodborne illness in the United States, according to the Centers for Disease Control and Prevention. More than 60 million men, women and children in the U.S. carry the Toxoplasma parasite, but very few have symptoms because the immune system usually keeps the parasite from causing illness.

Earlier research has shown that toxoplasmosis poses a threat to previously uninfected pregnant women and individuals who have compromised immune systems.

To prevent risk of toxoplasmosis and other infections from food, Dr. Robert Citronberg, director of the Division of Infectious Diseases at Advocate Lutheran General Hospital in Park Ridge, Ill., recommends the following:

• Don’t feed cats raw or undercooked meats.
• If you own a cat, change the litter box daily and wash your hands after changing the litter box.
• If you’re pregnant, avoid changing cat litter and don’t get a new cat.
• Don’t eat undercooked meat.
• Peel or wash fruits and vegetables thoroughly.
• Wash cutting boards and hands after contact with raw meat.
• Wear gloves when gardening and teach kids to wash their hands after playing with sand because the soil and sand might be contaminated with cat feces that contain toxoplasma.

“While this recent study extends brain science related to aggression, it does not prove that toxoplasmosis causes anger problems, much less that treatment of toxoplasmosis would reduce aggression or anger problems,” says Dr. Daniel Anzia, chair of psychiatry at Advocate Lutheran General Hospital in Park Ridge, Ill.

“People with serious anger problems that distress themselves or their families and friends should seek evaluation by a medical behavioral professional, such as a psychiatrist,” he says.