Larry, the Prime Minister's cat, sits outside No10  Photo: Steve Back

Owning a cat can lead to mental health problems, study warns

A parasite found in cat faeces may alter people's brain chemistry to cause long-term behavior problems 

 By Adam Boult

 30 Mar 2016

If you're prone to sudden bursts of anger, it could be your cat's fault.

A new study has found that people with Intermittent Explosive Disorder (IED) - characterised by explosive bouts of rage - are twice as likely to have been infected by a parasite found in cat faeces.

The findings suggest that toxoplasmosis, an infection from the parasite Toxoplasma gondii, may alter people's brain chemistry to cause long-term behavior problems.

Cats are known to pass the parasite on to human by shedding its eggs in their faeces. People can become infected by not washing their hands after cleaning a cat's litter tray, and then unintentionally ingesting the eggs.

Around a third of people in the UK will become infected at some point in their lives - with cat owners at particularly high risk.

Toxoplasmosis has also been linked with schizophrenia, bipolar disorder, impulsivity and suicidal behavior in earlier studies.

The new study, published in the Journal of Clinical Psychiatry, looked at 358 adult participants. Researcher found that 22 percent of the people with IED tested positive for toxoplasmosis exposure, compared with only 9 percent of those without IED.

 
 Road rage can be a manifestation of Intermittent Explosive Disorder  Photo: Alamy

"Not everyone that tests positive for toxoplasmosis will have aggression issues," said research leader Dr. Emil Coccaro of the University of Chicago. However, exposure to the parasite does appear to "raise the risk for aggressive behavior."

The NHS says that toxoplasmosis is "usually nothing to worry about because the immune system is normally strong enough to fight the infection and stop it from causing serious illness.

"After getting the infection, most people are immune to it for the rest of their life."

However, it can lead to serious problems in women who become infected while they're pregnant, and people with weak immune systems.