Mild vs. moderate: How behavioral speech measures predict metacognitive capacity across different levels of formal thought disorder.

Disorganized speech is a key component of formal thought disorder (FTD) in schizophrenia. Recent work has tied disorganized speech to deficits in metacognition, or one's ability to integrate experiences to form complex mental representations. The level of FTD at which differences in metacognitive capacity emerge remains unclear. Across two studies, using different cut scores to form FTD groups, we aimed to 1) explore the relationship between disorganized speech and metacognition and 2) compare trained rater and automated analysis methods. Clinical interviews were coded for disorganized speech and metacognition using the Communication Disturbances Index (CDI), Coh-Metrix multidimensional indices, and Metacognition Assessment Scale. In Study 1, we examined CDI and Coh-Metrix's ability to predict metacognition in FTD (n = 16) and non-FTD (n = 29) groups. We hypothesized the FTD group would have lower metacognition and that both CDI and Coh-Metrix would account for significant variance in metacognition. In Study 2, we conducted the same analyses with an independent sample using more stringent FTD cut scores (FTD: n = 23; non-FTD: n = 23). Analyses indicated that at a moderate but not mild cutoff: 1) automated methods differentiated FTD and non-FTD groups, 2) differences in metacognition emerged, and 3) behavioral measures accounted for significant variance (34%) in metacognition. Results emphasize the importance of setting the FTD cutoff at a moderate level and using samples that contain high levels of FTD. Findings extend research linking FTD and metacognition and demonstrate the benefit of pairing trained rater and automated speech measures.