Cat parasite studied for possible role in schizophrenia

BALTIMORE - Johns Hopkins University scientists trying to determine why people develop serious mental illness are focusing on an unlikely factor: a common parasite spread by cats.

The researchers say the microbes, called Toxoplasma gondii, invade the human brain and appear to upset its chemistry - creating, in some people, the psychotic behaviors recognized as schizophrenia.

If tackling the parasite can help solve the mystery of schizophrenia, "it's a pretty good opportunity . . . to relieve a pretty large burden of disease," said Dr. Robert H. Yolken, director of developmental neurobiology at the Johns Hopkins Children's Center.

Schizophrenia's cause is unknown, but both genetic and environmental factors likely play a part, according to the National Institute of Mental Health. Yolken is among researchers worldwide examining whether certain viral infections can increase the risk of developing the illness. Other studies have focused on viruses as possible triggers.

The notion that there are links between infections and schizophrenia is "intriguing," said Dr. Ken Duckworth, a clinical psychiatrist and medical director for the National Alliance on Mental Illness.

Yolken, a cat owner who says he has tested positive for Toxoplasma antibodies, said the potential link between Toxoplasma infections and mental illness is no reason for cat owners to panic - just to keep basic hygienic precautions in mind.