Detection of Cognitive Subtypes of Schizophrenia (with Assessment of Perceptual Disorders). A Pilot Study

Abstract

Background: the heterogeneity of schizophrenia impedes our efforts to provide adequate treatment. One step toward optimizing treatment is to deepen our understanding of cognitive variety in this disorder. Perhaps due to this heterogeneity, although visual impairment is a frequent symptom of schizophrenia, many studies show inconsistent data. The aim of our study was to identify homogeneous groups of patients with schizophrenia based on susceptibility to the Ponzo illusion, cognitive impairment degree (BACS T-score) and severity of mental state during therapy (Total PANSS score) and to examine the relationship between clinical parameters and the value of the illusion. Patients and methods: a prospective six-week observational study included 30 patients with the paranoid form of schizophrenia in the second week of stable antipsychotic monotherapy, 11 of whom dropped out due to exclusion criteria. At the second and eighth weeks of treatment, patients were assessed for susceptibility to the Ponzo illusion, cognitive impairment using a battery of BACS tests, and severity of mental status during a semi-structured interview using the PANSS scale. Results: the cluster analysis identified 2 clusters of patients who differed in their susceptibility to the Ponzo illusion. Patients in the first cluster (n = 9) with a significantly higher score on negative PANSS symptoms and marked cognitive impairment in the second and eighth weeks of therapy were prone to overestimate the Ponzo illusion, while patients in the second cluster (n = 10) were less susceptible to the Ponzo illusion. Conclusions: this study allowed us to identify two clusters of patients differing in the severity of cognitive and visual impairments, the relationship of susceptibility to Ponzo illusion with such clinical indicators as negative and cognitive symptoms was demonstrated, which confirms the informative value of using the visual illusion methodology as a marker of mental state.