Study Says Biomarker Can Predict Schizophrenia Patients’ Stress Tolerance
New research indicates the salivary levels of the endogenous neuromodulator kynurenic acid (KYNA) can identify patients with schizophrenia who are likely to be intolerant of stress.
“Importantly, we have uncovered a potential biomarker separating a subgroup of patients with schizophrenia displaying a particular maladaptive behaviour”, say lead study author Joshua Chiappelli, from the Maryland Psychiatric Research Center, Baltimore, and his colleagues.
The study compared 64 schizophrenia patients against healthy control participants and found that the schizophrenic group was significantly more often distress intolerant when matched for age, gender, and smoking status. Both groups undertook two computer-based tasks which were difficult enough to cause some participants to drop out of the study despite the promise of a monetary reward for persistence.
Close to 40% of the patients with schizophrenia quit both tasks, compared with under 20% of the control group, as the team reported in JAMA Psychiatry.
The researchers saw that the patients had higher baseline KYNA levels than their control counterparts, and the stressful tasks induced a transient rise to a similar extent in both groups. Among the distress tolerant participants, defined as those who completed at least one task, the pattern of KYNA change was similar in both groups.
On the other hand, among the distress intolerant participants who quit both tasks, the schizophrenia patients had a significantly more drastic increase in KYNA levels than the control members.
Daniel Javitt, from Columbia University College of Physicians and Surgeons, New York, highlights the findings that “patients may be more stressed than controls, even by simple tasks such as arithmetic or mirror drawing,” in an editorial accompanying the study.
He says: “This must be taken into account when asking patients to participate in other mentally demanding activities, such as cognitive remediation or supported employment.”