The Relationship between Language Ability and Cognitive Function in Patients with Schizophrenia

OBJECTIVE: Cognitive dysfunction is common in people with schizophrenia, and language disability is one of the most notable cognitive deficits. This study assessed the use and comprehension ability of the Korean language in patients with schizophrenia and the correlations between language ability and cognitive function. METHODS: Eighty-six patients with schizophrenia and a group of 29 healthy controls were recruited. We assessed both clinical symptoms and cognitive functions including Korean language ability. For clinical symptoms, the Positive and Negative Syndrome Scale, Clinical Global Impression-Schizophrenia Scale, and Social and Occupational Functioning Assessment Scale were used. For the Korean language ability assessment, a portion of the Korean Broadcasting System (KBS) Korean Language Test was used. The Short-form of Korean-Wechsler Adult Intelligence Scale, the Korean version of the University of California San Diego (UCSD) Performance-based Skills Assessment (K-UPSA), and the Wisconsin Card Sorting Test (WCST) were used to assess cognitive functions. RESULTS: Schizophrenic patients had significantly lower scores in the language and cognitive function tests both in the total and subscale scores. Various clinical scores had negative correlations with reading comprehension ability of the KBS Korean Language Test. The WCST and a part of the K-UPSA had positive correlations with multiple domains of the language test. CONCLUSION: A significant difference was found between schizophrenic patients and controls in language ability. Correlations between Korean language ability and several clinical symptoms and cognitive functions were demonstrated in patients with schizophrenia. Tests of cognitive function had positive correlations with different aspects of language ability.