Johns Hopkins researchers have identified a chemical marker in cerebral spinal fluid that may help doctors treat and diagnose individuals with schizophrenia.

"Finding this activity in CSF could give us the first real tool for identifying patients with schizophrenia," says Frances Yee, a postdoctoral fellow at the Stanley Neurovirology Laboratory.

For several years, researchers have found evidence that retroviruses may be associated with some cases of schizophrenia. Because retroviruses can't reproduce by themselves, they exploit living host cells and use an enzyme called reverse transcriptase to copy themselves into host genomes and replicate. In 1998, Yee and colleagues discovered that individuals with schizophrenia had higher levels of RT enzyme activity in their post-mortem brain tissue.

As a next step, researchers tested activity levels of this enzyme in the CSF of 18 schizophrenic patients and 18 similar individuals unaffected by the disease. The researchers found that patients with a recent onset of schizophrenia had significantly higher levels, almost a fourfold increase, of RT activity in their CSF in comparison to the controls.

Yee and her team plan to launch a study in a larger group of patients and have hopes that, in the future, this marker could be used to diagnose and treat schizophrenia. "If you have a marker where you can say, 'If this goes up, they are going to have a psychotic episode,' then you might use a slightly different mix of drugs to treat them," Yee says.

Results of Yee's study were reported at the Fifth Annual Symposium on the Neurovirology and Neuroimmunology of Schizophrenia and Bipolar Disorder, which was held in November in Bethesda, Md.