WORKING-MEMORY CAPACITY PREDICTS LANGUAGE COMPREHENSION IN SCHIZOPHRENIC-PATIENTS

The association between language comprehension and working memory capa city was evaluated in 25 male DSM-III-R schizophrenic patients (14 inp atients; 11 outpatients), and in 11 male normal controls (no lifetime DSM-III-R disorder). Patients and controls did not differ significantl y on age and education. Language comprehension was examined as a funct ion of two types of processing demand: grammatical complexity (complex versus simple sentences) and presentation rate (accelerated versus co nversational). Schizophrenic patients showed significantly reduced lan guage comprehension and decreased working memory capacity for language , compared with controls. Patients showed general difficulty in compre hending accurately, rather than exhibiting problems with specific gram matical structures. Subject groups were highly accurate and did not di ffer in their ability to perceive the individual words in sentences pr esented at the accelerated rate (intelligibility). Presentation rate a nd grammatical complexity affected comprehension accuracy in all group s, however, with increases in rate and complexity producing decreases in understanding. Of most importance, theoretically, is the finding th at working memory capacity predicted language comprehension accuracy i n both schizophrenic patients and normal controls. Results suggest tha t language comprehension deficits in schizophrenic patients may involv e a general dysfunction that is associated with working memory capacit y for language.