Currently it is well known that schizophrenia is associated with cognitive impairment. Still there are many unresolved questions, such as whether cognitive deficit is total, what are the relationships of cognitive impairment with clinical features, demographic characteristics and different biomarkers, which could shed light on its pathogenesis. The aim of our study was to characterize cognitive impairment in schizophrenia and to find factors that may contribute to it. Sixty patients with paranoid schizophrenia were examined. BACS, Rey-Osterreith complex figure and correction task were used to assess cognitive functioning. Only 14.3% of patients had BACS score in the normal range. The vast majority of them showed impaired motor function, verbal and visual memory. Cognitive functioning did not worsen with time. Working memory impairment was influenced by genetic predisposition to schizophrenia and age of disease onset. Residual positive symptoms led to a decrease in the speed of skill development. Symptoms of anxiety and depression contributed to the impairment of accuracy. Hypomania was associated with impaired planning. Planning and problem-solving behavior did not correlate with other cognitive functions, which makes them isolated domains. Higher levels of NSE had been found in patients with more severe memory impairment. S100B level was associated with safer constructive abilities. In general, cognitive impairment in schizophrenia, although present in the majority of patients, varies a lot and appears selective and dependent on certain clinical features.

The study was supported by RSCF 14-50-00069 grant.