While schizophrenia is a complex psychiatric disorder that has its roots in genetic changes, researchers at Johns Hopkins University have uncovered a potentially new culprit for some of the condition’s most common symptoms.
Reporting in the journal Schizophrenia Research, the psychiatrists describe a connection between the herpes simplex virus, responsible for cold sores, and the drop in concentration, memory and coordination that are often the earliest signs of schizophrenia. Previous studies have linked the presence of antibodies to the virus with both smaller brain volumes and cognitive problems in patients with the mental disorder.
So the Hopkins researchers, led by David Schretten, studied blood samples from 40 schizophrenic patients and asked these volunteers to perform a series of cognitive tests. Their findings confirmed that indeed, those who had herpes simplex antibodies, indicating that they had fought off an infection with the virus, scored lower on the tests of coordination, memory and motor skills than patients not possessing the same antibodies. In addition, brain scans confirmed that the patients who performed poorly on the cognitive tests also had smaller brain volumes than those who hadn’t been exposed to the virus. In particular the cerebellum, which controls motor function, was considerably smaller in these subjects.
These results lead the authors to believe that the herpes virus may be directly attacking brain tissue and triggering the cognitive deficits, and that somehow, the schizophrenic brain is more vulnerable to the viral assault. That suggests that there may be new ways to control the symptoms of schizophrenia by helping patients to prevent or control exposure to herpes simplex by reducing the number of cold sores they get.
In addition, since the cognitive problems are a prelude to the more severe symptoms of hallucinations and delusions that occur later on in schizophrenia, Schretten suggests that testing patients suspected of having the disorder for the presence of herpes simplex virus, and controlling the infection, may help to reduce the range and severity of cognitive symptoms.