Women who are infected with the common cat parasite Toxoplasma gondii may be more vulnerable to suicide, a new study finds, adding to the evidence that T. gondii or Toxo, as the bug is known, may cause subtle changes in the human brain that lead to personality changes and even mental illness.

The parasite is excreted in cat feces — which is why pregnant women are advised not to change the litter box — but it also spreads through undercooked meat and unwashed vegetables. Pregnant women who become infected with T. gondii can pass it onto their fetus, possibly causing brain damage or stillbirth. Now the new study finds that expectant mothers who have the infection, called toxoplasmosis, may themselves be at higher risk of suicide.

The finding comes from a study of 45,788 Danish women who gave birth between May 15, 1992, and January 15, 1995. University of Maryland School of Medicine researchers tested the women’s babies for T. gondii antibodies, which the infants could only have acquired from their mothers, and compared infection rates to the women’s suicide rates logged in the Danish health registry. The team also cross-checked the mental health registry to find out if any of the women had been previously diagnosed with mental illness. Read more at Time