The study was done on U.S. military personnel by researchers from Walter Reed Army Institute of Research and Johns Hopkins Children's Center. Findings of the study appear in the January issue of the American Journal of Psychiatry.
About 2 million Americans have schizophrenia.
According to the National Institute of Mental Health, "Schizophrenia is a chronic, severe and disabling brain disorder that affects about 1.1 percent of the U.S. population age 18 and older in a given year. People with schizophrenia sometimes hear voices others don't hear, believe that others are broadcasting their thoughts to the world or become convinced that others are plotting to harm them. These experiences can make them fearful and withdrawn and cause difficulties when they try to have relationships with others."
Researchers studied 180 people who were diagnosed with schizophrenia and found that 7 percent of them had been infected with toxoplasma prior to their diagnosis, compared to 5 percent among the 532 healthy recruits.
That means that people exposed to toxoplasma had a 24 percent higher risk of developing schizophrenia.
Researchers say that even though that difference seems small that it is important because if scientists can explain how even a small percentage of schizophrenia cases occur in the United States that they will have important clues and insights into the disease that might lead to some possible treatments.
"Our findings reveal the strongest association we've seen yet between infection with this very common parasite and the subsequent development of schizophrenia," Robert Yolken, M. D., a neurovirologist at Hopkins Children's who was among those conducting the analysis, said in a press statement.
