An Investigation Into Semantic Network and Its Psychopathology Correlates in Schizophrenia

Abstract

Background: Disturbance of association is a hallmark feature of schizophrenia (Bleuler, 1911). The mechanism under the disturbance and how it relates to psychopathology are, however, yet to be understood. Using new methods of network analysis, the current study aims to explore the relationship between network measures and symptoms in schizophrenia by comparing the network measures between patients and healthy subjects, and within patients across time points. Methods: The current study uses continued word association task to derive semantic network in participants. Each participant would be asked to provide 3 words associated to a cue words. The list of 200 cue words has been preselected from a list of Cantonese words and is representative of the overall list in terms of valence, concreteness, and part-of-speech composition. Forty patients with schizophrenia-spectrum disorders would be recruited at either first episode or relapse when they experience active psychotic symptoms and followed up at 6 months. Forty matching control subjects would also be recruited. Neurocognitive measures and clinical measures on symptoms severity, insights, functioning, and language disorders would also be collected. Results: Recruitment started in mid-August, 2016. Currently, 8 patient subjects and 8 matching healthy subjects have been recruited. The mean age of the patient subjects is 40 years old (SD = 9.8), with an average overall PANSS score of 56.1 (SD = 10.3), SAPS score of 18 (SD = 9.5), SANS score of 14.4 (SD = 11.6), CDSS score of 5.4 (SD = 5.1), YMRS score of 1.7 (SD = 2), and SUMD score of 5.5 (SD = 2.2). For the semantic network, basic measures including response overlap, response similarity, response congruency, and the valence and concreteness measures of the responses would be calculated. When the complete set of data is ready, further investigation into network measures such as clustering coefficients, average path length, and network diameter can also be conducted and presented. Conclusion: The study can be able to provide insights into the disturbances in semantic network in patients with schizophrenia, the stability of the disturbances, and how it correlates with neurocognitive and clinical measures. The longitudinal design also allows for investigation into whether and how the semantic disturbances at baseline could predict the clinical and neurocognitive properties of patients at 6-month follow-up.