"Ask" or "Inquire": operationalizing speech formality in psychosis and its risk states using etymology

Many individuals with psychotic symptoms have less complex language than healthy individuals. Word etymology is a lexical feature that has not yet been studied in clinical populations, but among healthy individuals, words of Old French origin are chosen over Germanic-origin words to convey formality (e.g. "inquire" vs. "ask"). Differences in language complexity among individuals with psychotic symptoms may relate to differences in etymological content in speech. Here, we determined the proportion of Germanic-origin word use and Old-French-origin word use in a large cohort of individuals with recent-onset psychosis or at clinically high risk for psychosis, hypothesizing that individuals with recent onset psychosis would have increased use of Germanic-origin words and decreased use of Old-French-origin words. This hypothesis was borne out, even after adjusting for sex, age, recruitment site, education, racial identity, and for a subset, IQ. Etymology proportions were associated with role but not social functioning in individuals with psychotic symptoms, consistent with the premise that they reflect speech formality. Understanding speech differences in the psychosis spectrum through the lens of etymology may lead to new interventions to improve role functioning.