Differences in cognitive function and daily living skills between early- and late-stage schizophrenia

Cognitive dysfunction is a core feature of schizophrenia; deficits often manifest prior to diagnosis and persist throughout the course of the illness. This study was performed to assess the difference in cognitive function and daily living skills between the early- and late-stage schizophrenia.

Fifty-five clinically stable patients with schizophrenia were recruited (25 with < 5-year and 30 with > 5-year disease durations). We evaluated subjects' clinical states, cognitive function, and psychosocial factors. The Korean versions of MATRICS Consensus Cognitive Battery and UCSD Performance-based Skills Assessment were used for evaluating cognitive function and daily living skills. Chi-square, Wilcoxon rank sum, and t-tests were used to analyze the data.

The two groups did not differ for most demographic variables. No significant differences between groups were found for clinical symptoms, psychosocial factors, or non-social cognitive domains. However, the early-stage group had higher social cognition domain scores than the late-stage group (p = 0.01). Early-stage patients scored significantly higher than those in the late-stage group did in the communication and comprehension/planning domains (p = 0.037 and 0.027, respectively), and total score (p = 0.003) of the Performance-based Skills Assessment.

We observed significant differences between patients with early- and late-stage illness with regard to social cognition and performance-based skills.