Palominos Claudio, He Rui, Fröhlich Karla, Mülfarth Rieke Roxanne, Seuffert Svenja, Sommer Iris E, Homan Philipp, Kircher Tilo, Stein Frederike, Hinzen Wolfram
Department of Translation & Language Sciences, Universitat Pompeu Fabra, Barcelona, Spain.
Department of Psychiatry and Psychotherapy, University of Marburg, Marburg, Germany.
Schizophrenia (Heidelb). 2024 Dec 2;10(1):114. doi: 10.1038/s41537-024-00524-7.
Large language models provide high-dimensional representations (embeddings) of word meaning, which allow quantifying changes in the geometry of the semantic space in mental disorders. A pattern of a more condensed ('shrinking') semantic space marked by an increase in mean semantic similarity between words has been recently documented in psychosis across several languages. We aimed to explore this pattern further in picture descriptions provided by a transdiagnostic German sample of patients with schizophrenia spectrum disorders (SSD) (n = 42), major depression (MDD, n = 43), and healthy controls (n = 44). Compared to controls, both clinical groups showed more restricted dynamic navigational patterns as captured by the time series of semantic distances crossed, while also showing differential patterns in the total distances and trajectories navigated. These findings demonstrate alterations centred on the dynamics of the flow of meaning across the semantic space in SSD and MDD, preserving previous indications towards a shrinking semantic space in both cases.
大语言模型提供了词意的高维表示（嵌入），这使得对精神障碍中语义空间几何结构的变化进行量化成为可能。最近，在多种语言的精神病研究中都记录到了一种语义空间更为紧凑（“收缩”）的模式，其特征是词之间的平均语义相似度增加。我们旨在通过德国一个跨诊断样本的患者提供的图片描述，进一步探索这种模式。该样本包括精神分裂症谱系障碍（SSD，n = 42）、重度抑郁症（MDD，n = 43）患者以及健康对照者（n = 44）。与对照组相比，两个临床组在穿越的语义距离时间序列所捕捉到的动态导航模式上表现出更多限制，同时在总距离和导航轨迹上也表现出不同模式。这些发现表明，SSD和MDD中以语义空间中意义流动的动态为中心存在改变，这与之前在这两种情况下语义空间收缩的迹象一致。
