Cognitive impairment in schizophrenia across age groups: A case-control study

Abstract

Background: The potential dynamics of cognitive impairment in schizophrenia is discussed in the literature of the field. Recent publications suggest modest changes in level of cognitive impairment after first psychotic episode. Present article attempts to explore cognitive differences between patients and controls across age groups and differences between age groups in clinical group. Methods: One hundred and twenty-eight hospitalized patients with schizophrenia (64 women and 64 men) and 68 individuals from the control group (32 women and 32 men) aged 18-55 years were examined. The patients were divided into age groups (18-25, 26-35, 36-45, 46-55). Both groups were examined using Wisconsin Card Sorting Test, Rey Auditory Verbal Learning Test, Rey Osterrieth Complex Figure Test, Trail Making Test (A and B), Stroop Test, verbal fluency test and Wechsler digit span. Results: Patients with schizophrenia obtained significantly lower scores versus the control group in regard to all the measured cognitive functions (Mann-Whitney U; p<0.05. Most deficits were present in all age groups, however, statistically important impairment in executive functions (WCST) were present only in "older" groups. Conclusions: Patients with schizophrenia obtained less favourable results than the control group in all age groups. Deficits regarding executive functions do not seem to be at a significant level among the youngest group, whereas they are more noticeable in the group of 46-55-year-olds. Executive functions are significantly lowered in the group aged 36-45 in comparison to the "younger" groups. The level of cognitive functions shows a mild exacerbation in connection with age, whereas cognitive rigidity proved to be related to the number of years spent without hospital treatment.