Semantic Processing of Emotional Words in Schizophrenia

Abstract

Schizophrenia (SZ) is associated with devastating emotional, cognitive and language impairments. A better understanding of the interaction and neuropathology of deficits will have important therapeutic implications. This study tested whether negative word perception is impaired in subjects with SZ compared to healthy controls (HC), and correlates with the severity of emotional and cognitive deficits. SZ and HC subjects were scanned with functional magnetic resonance imaging (fMRI) while silently reading negative paranoia-themed and neutral words. Post-scan, subjects rated the valence of each word. The effects of group (SZ, HC), word type (negative, neutral), task period (early, late), and clinical symptoms (positive, negative, excitement/hostility, cognitive impairment, depression/anxiety), on word valence ratings and fMRI responses were analyzed. SZ versus HC subjects rated the neutral words as more positive, and the subgroup with severe excitement/hostility symptoms rated the negative words as more negative. SZ versus HC subjects hyperactivated the left posterior middle temporal and angular gyri in response to the negative words. Activation to the negative words in left dorsal temporal pole, and to neutral words in left middle temporal gyrus, was positively correlated with the excitement/hostility scores. In contrast, activation in limbic/paralimbic areas was positively correlated with cognitive impairment scores. The results point to an emotionally exaggerated response to paranoia-themed and neutral words in SZ, that is related with excitement/hostility symptoms, and may be mediated by hyperactivation of a left-lateralized temporoparietal semantic network associated with knowledge of emotion concepts. Thus, emotional word semantic processing may be an important psychotherapeutic target in SZ.