The relationship between atypical semantic activation and odd speech in schizotypy across emotionally evocative conditions

Introduction: Odd speech is prevalent in individuals with schizotypy compared to controls and this odd speech is particularly pronounced under stress-induced conditions. Despite a number of research studies that have examined odd speech, the mechanisms underlying this phenomenon remain unclear. There is reason to suspect that the increase in odd speech observed in schizotypy may reflect atypical semantic activation patterns, defined in terms of increased activation of weakly associated words within the semantic network. Methods: In this study, we compared atypical semantic activation in individuals with a broad set of cognitive-perceptual, interpersonal and disorganization schizotypal traits (n = 83) and controls (n = 23). Odd speech was measured using a behavior-based analysis of natural speech procured from a laboratory speech-task involving separate experimentally manipulated stressful, pleasant, and neutral conditions. Results: The schizotypy and control groups did not differ in semantic activation, but atypical semantic activation was more pronounced in individuals with disorganization traits and attenuated in those with interpersonal traits. Interestingly, the relationship between semantic activation and odd speech was observed for the stressful, but not pleasant or neutral conditions in the schizotypy group. Conclusions: These findings suggest that individuals with schizotypy may be able to inhibit atypical associations in nonstressful situations. However, their ability to prevent atypical semantic activation from affecting speech may be disrupted under stress, thus resulting in more odd speech. This study also highlights the dramatic differences in semantic activation across the various manifestations of schizotypy.