Computational linguistic analysis applied to a semantic fluency task: A replication among first-episode psychosis...

Automated tools do not yet exist to measure formal thought disorder, including derailment and tangentiality, both of which can be subjectively rated using the Scale for the Assessment of Positive Symptoms after a clinical research interview. CoVec, a new automated tool, measures the semantic similarity among words averaged in a five- and ten-word window (Coherence-5 and Coherence-10, respectively). One prior report demonstrated that this tool was able to differentiate between patients with those types of thought disorder and patients without them (and controls). Here, we attempted a replication of the initial findings using data from a different sample of patients hospitalized for initial evaluation of first-episode psychosis. Participants were administered a semantic fluency task and the animal lists were analyzed with CoVec. In this study, we partially replicated the prior findings, showing that first-episode patients with derailment had significantly lower Coherence-5 and Coherence-10 compared with patients without derailment. Further research is warranted on this and other highly reliable and objective methods of detecting formal thought disorder through simple assessments such as semantic fluency tasks.