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Strong link found between cat ownership and mental illness

The authors of a new study say evidence of a link between schizophrenia and T. gondii, a parasite found in cat feces, is The authors of a new study say evidence of a link between schizophrenia and T. gondii, a parasite found in cat feces, is "overwhelming." Firelong / Pixabay

A disturbing new study published in the journal Schizophrenia Research has found that cat ownership during childhood increases the risk of being diagnosed with schizophrenia later in life. The reason: exposure to Toxoplasma gondii, a parasite that is present in cat feces.

The researchers, led by Robert H. Yolken, M.D., of  the Stanley Laboratory of Developmental Neurovirology at the Johns Hopkins University School of Medicine and E. Fuller Torrey of the Stanley Medical Research Institute, compared an unpublished survey on mental illness from 1982 and two later studies, which found an association between long-term childhood exposure to cats and the development of serious mental illnesses, including schizophrenia and bipolar disorder.

“Cat ownership in childhood has now been reported in three studies to be significantly more common in families in which the child is later diagnosed with schizophrenia or another serious mental illness,” said the authors in a statement.

Toxoplasma gondii can infect any warm-blooded animal, including humans. Although most people exposed to the parasite show no symptoms, people with weakened immune systems can be seriously affected. The parasite causes an illness called toxoplasmosis, a condition giving rise to flu-like symptoms, blindness, miscarriage, and abnormal fetal development, a report by Medical Daily said.

According to estimates by the U.S. Centers for Disease Control and Prevention (CDC), more than 60 million people in the nation may be infected with T. gondii.

The new study corroborates other recent research published in the journal Acta Psychiatrica Scandinavica by scientists at the Academic Medical Centre in Amsterdam in the Netherlands. Those researchers, who analyzed the results of 50 previously published studies, confirmed the link between infection with T. gondii and the development of mental disorders.

“In schizophrenia, the evidence of an association with T. gondii is overwhelming,” say the authors, adding that the findings may shed additional light on the relationship between toxoplasmosis and the risk of developing psychiatric disorders.

Do the findings mean children must be kept away from cute, cuddly felines? No, said Torrey in an email to CBS News.

“Children can be protected by keeping their cat exclusively indoors and always covering the sandbox when not in use,” he wrote. Also, it is important to change a cat’s litter box on a daily basis, according to CDC recommendations, because T. gondii is not infectious until between 1 and 5 days after the kitty poops.

Researchers also have found a correlation between infection with T. gondii, obsessive-compulsive disorders, and addiction, the CBS News report said.

Delila James

Delila James

Associate Editor/Writer
Delila James practiced civil rights and employment law for almost 20 years. Before going to law school, she raised organic lamb on a ranch in the Sierra Nevada foothills, ran a dairy farm in Muscoda, WI, and then owned a popular live music nightclub in Madison, WI. She has a Master's degree in the History of Science from the University of Wisconsin-Madison, where she went to law school. She also is a published poet. She now is a book editor, writes legal blogs, and is trying to finish a book. She has been writing for Science Recorder since March, 2013.
About Delila James (1327 Articles)
Delila James practiced civil rights and employment law for almost 20 years. Before going to law school, she raised organic lamb on a ranch in the Sierra Nevada foothills, ran a dairy farm in Muscoda, WI, and then owned a popular live music nightclub in Madison, WI. She has a Master's degree in the History of Science from the University of Wisconsin-Madison, where she went to law school. She also is a published poet. She now is a book editor, writes legal blogs, and is trying to finish a book. She has been writing for Science Recorder since March, 2013.