Small Words That Matter: Linguistic Style and Conceptual Disorganisation in Untreated First Episode Schizophrenia

This study aimed to shed light on the linguistic style affecting the communication-discourse in First Episode Schizophrenia (FES) by investigating the analytical thinking index in relation to clinical scores of conceptual and thought disorganization (Positive and Negative Syndrome Scale, PANSS-P2 and Thought and Language Index, TLI). By using robust Bayesian modeling, we report three major findings: (1) FES subjects showed reduced analytical thinking, exhibiting a more narrative linguistic style than healthy control (HC) subjects (Bayes factor, BF10 > 1000), despite using the same proportion of function and content words as HCs; (2) the lower the analytic thinking score, the higher the symptoms scores of conceptual disorganization (PANSS-P2, BF = 22.66) and global disorganization of thinking (TLI, BF10 = 112.73); (3) The linguistic style is a better predictor of conceptual disorganization than the cognitive measure of processing speed in schizophrenia. These findings, on the one hand, provide an objectively detectable linguistic style in schizophrenia that requires no clinical judgment; on the other hand, they provide a crucial insight into the primacy of linguistic structural disruption in clinically ascertained disorganised thinking in schizophrenia. Furthermore, PANSS-P2 and TLI disorganisation scores are notably influenced by this linguistic style, rather than cognitive deficits such as processing speed reduction. Our work contributes to an emergent body of literature on the linguistic basis of the psychopathology of schizophrenia. At an utilitarian level, this has implications for improving social and educational outcomes in this illness.