Co-reference and the topology of meaning in schizophrenia and depression

Studies using semantic measures from language models in psychopathology have predominantly focused on lexical-conceptual meaning, while the referential aspect of meaning has been targeted less. Here, we compare the performance of an automatic coreference resolution model across healthy controls (HC, n = 36), schizophrenia spectrum disorder (SSD, n = 41), and major depressive disorder (MDD, n = 42). We tested the hypothesis that co-reference in these clinical populations would be harder to resolve for such models. We then relate model performance to semantic and coreferential structure, employing a topological approach with speech graphs of both referential and lexical-semantic meaning. Results confirmed lower model performance in both SSD and MDD compared to controls, and a reduced structural divergence between semantic and referential graphs in SSD. Within SSD, model performance negatively correlated with positive symptoms, while in MDD, it was associated with verbal memory measures, suggesting partially distinct underlying mechanisms. These results newly profile lexical-conceptual and referential-semantic alterations against each other, linking two dimensions of meaning in a more integrated foundational model of language in major psychopathology.