SOCIAL COGNITION AND OXIDATIVE STRESS IN SCHIZOPHRENIA PATIENTS AND FIRST-DEGREE RELATIVES OF PATIENTS

Misattribution of motivational salience to non-salient (neutral) stimuli could be viewed as a hallmark of psychosis in schizophrenia. Studies have recently revealed increased subjective experience of emotional arousal (EA) to neutral social stimuli in paranoid schizophrenia psychosis, suggesting a misattribution of emotional salience to them. We examined this phenomenon directly by quantifying the level of EA subjectively attributed to low-arousal, neutral-valenced faces.

Patients with remitted schizophrenia (PG) (n=26), first-degree relatives of schizophrenic patients (RG) (n=25), and healthy controls (HCG) (n=36) were compared in terms of oxidative stress parameters -serum Superoxide Dismutase, Catalase, Glutathione Peroxidase (GPx), Nitrite, Nitrate, Malondialdehyde, and Total Glutathione levels-, social cognition measured by the Reading the Mind in the Eyes Test and working memory measured by the N-back Task. Groups were compared, assuming that HCG had a genetically lower risk of schizophrenia compared to PG and RG.

HCG performed significantly better than PG and RG, who were genetically at high risk, in terms of social cognition (respectively p=0.000, p=0.014), working memory (respectively p=0.001, p=0.003), and had statistically lower Glutathione Peroxidase (GPX) level than the PG and RG (both p:0.000). After controlling for the effect of the general intellectual abilities measured by the Raven Standard Progressive Matrices Test and working memory the differences between groups on the Eyes Test disappeared (p=0.057). However, this value tended to be significant.

It was concluded that social cognition and working memory and GPx level may be used as endophenotypes and social cognition, working memory, and general intellectual skills are different but strongly related constructs. Endophenotypes guide treatment targets even after the disease has developed. The results of our study showed that in addition to psychopharmacological treatments, interventions to reduce oxidative stress and approaches to improve cognitive skills will have a positive impact on the disease's progression.