Amy says I can be an asshole.

She’s not the only one; but I.can blame it on the toxo.

Better than blaming parents.

Tori Rodriguez writes in Scientific American that people who feel sociable or reckless may have toxoplasmosis, an infection caused by the microscopic parasite Toxoplasma gondii, which the CDC estimates has infected about 22.5 percent of Americans older than 12 years old.

Researchers tested participants for T. gondii infection and had them complete a personality questionnaire. They found that both men and women infected with T. gondii were more extroverted and less conscientious than the infection-free participants. These changes are thought to result from the parasite’s influence on brain chemicals, the scientists write in the May/June issue of the European Journal of Personality.

“Toxoplasma manipulates the behavior of its animal host by increasing the concentration of dopamine and by changing levels of certain hormones,” says study author Jaroslav Flegr of Charles University in Prague, Czech Republic.

In the new study, a pattern appeared in infected men: the longer they had been infected, the less conscientious they were. This correlation supports the researchers’ hypothesis that the personality changes are a result of the parasite, rather than personality influencing the risk of infection. Past studies that used outdated personality surveys also found that toxoplasmosis-related personality changes increased with the length of infection.