Maryland researchers expand usefulness of schizophrenia biomarker found in saliva

A biomarker previously linked with schizophrenia and found in saliva seems to say more nuanced things about the disease than previously thought, based on a new study that involved computer stress tests.

The research team from the University of Maryland School of Medicine in Baltimore now believes that the biomarker's presence can also help identify schizophrenic patients dealing with acute stress who might not otherwise reveal it. Medscape Medical News reported on the finding, which is explained in detail in the latest issue of JAMA Psychiatry. The biomarker discovery could help boost the standard of care for schizophrenic patients, allowing doctors to intervene with drug treatments, psychiatric care or both when they might not have done so previously. More precisely, however, as the article explained, KYNA could serve as a specific target for new schizophrenia treatments if future research can repeat these initial findings.

As Medscape Medical News noted, doctors already knew that levels of kynurenic acid--an endogenous neuromodulator also known as KYNA--are higher in schizophrenic patients than in others, based on studies of brain tissue and cerebrospinal fluid of deceased people with schizophrenia.

This latest project looked at living patients, both with and without schizophrenia. Researchers studied 128 patients, split evenly between schizophrenia patients and a control group. By making their subjects complete laboratory-based computer stress tests relying on mental arithmetic and mirror drawing, they determined that schizophrenia patients more frequently quit their tasks early and had a much higher inability to handle the stress involved, according to the Medscape Medical News story. As well, these patients had a much higher average KYNA level in their saliva at baseline. KYNA did jump in both groups from baseline to completion of the computer stress tests. But KYNA levels were off the charts in patients who couldn't handle the tests in the first place.

Progress in the search for new schizophrenia-related biomarkers and diagnostic tools has unfolded in a number of ways. A group from King's College London and their colleagues said last year, for example, that they wanted to use levels of "folding" on the outside of the brain to predict whether schizophrenic or other patients would respond to antipsychotic drugs. Also in 2013, Virginia Commonwealth University School of Pharmacy researchers found a number of biomarkers connected to the transmission of brain signals and immunity that point to the risk of developing schizophrenia.

- read the Medscape Medical News story (reg. req.)
- here is the journal abstract