Background & Aims

Clinical findings demonstrated that patients with schizophrenia failing to respond to the pain of acute diseases, such as myocardial infarction and ruptured appendix [1-2]. Comparing with the consistency of clinical findings, a diminished response to experimental pain was found in chronic schizophrenia patients [3-4]. Notably, pain insensitivity is associated with increased morbidity and mortality among those patients [5-6]. However, the mechanism of altered pain sensitivity in schizophrenia has been poorly understood. The present study is aimed to clarify the underlying mechanism for the implement of clinical practice, thus facilitating the mental health of patients with schizophrenia.

Methods

Twenty-one right-handed schizophrenia patients (age = 37.6 ± 7.9; female = 5), together with twenty-one age-gender matched, right-handed healthy controls (age = 34.4 ± 7.2) were recruited at the inpatient and outpatient psychiatric services of Beijing Huilonguan Hospital. A stimulus-response paradigm with nociceptive stimuli to test the pain insensitivity in SCZ patients used EEG technique to clarify its neural mechanisms. EEG data transformed through Surface Laplacian were used for the Phase Lag Index (PLI) and the corresponding network analysis. The computation of PLI was applied in theta (4-8 Hz), alpha (8-13 Hz), and beta (14-30 Hz) frequency bands, irrespectively. The network-based statistical (NBS) analysis [7], controlled for family-wise error rate and employing 1000 permutation tests, was performed to identify distinct connectivity patterns between groups. Independent-samples t-test was applied to detect the between-subject differences in nociceptive ratings and network measur

Results

Schizophrenia patients (SP) showed significant lower nociceptive ratings compared to control subjects (SP = 3.69 ± 1.98; con = 5.42± 2.28, t = -3.83, p< 0.001). A significant network was found across all channels with larger theta band PLI connectivity in the control group compared to schizophrenia patients (P < 0.001). Significant differences were also observed in the network measurements of clustering coefficients (con = 0.82 ± 0.003, SP = 0.11 ± 0.0004, p< 0.001), connectivity strength (con = 3112.49 ± 43525.20, SP = 425.76 ± 6055.28, p< 0.001), and global efficiency (con = 1.23 ± 0.01, SP = 9.29 ± 2.70, p< 0.001). Additionally, significant correlations were also found between nociceptive ratings and the PLI values (R = 0.45, p = 0.004), clustering coefficients (R = 0.45, p = 0.004), connectivity strength (R = 0.46, p = 0.004), and global efficiency (R = -0.47, p = 0.003).

Conclusions

Our research suggested a general desynchronization of theta-band brain network in schizophrenia patients, which might lead them to pain insensitivity.

References

[1] Stubbs, B., Eggermont, L., Mitchell, A. J., De Hert, M., Correll, C. U., Soundy, A., Rosenbaum, S., & Vancampfort, D. (2015). The prevalence of pain in bipolar disorder: A systematic review and large-scale meta-analysis. Acta psychiatrica Scandinavica, 131(2), 75–88.
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[6] Rouch, I., Strippoli, M. F., Dorey, J. M., Ranjbar, S., Laurent, B., von Gunten, A., & Preisig, M. (2023). Psychiatric disorders, personality traits, and childhood traumatic events predicting incidence and persistence of chronic pain: Results from the CoLaus|PsyCoLaus study. Pain, 164(9), 2084–2092.
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[8] Rubinov, M., & Sporns, O. (2010). Complex network measures of brain connectivity: Uses and interpretations. NeuroImage, 52(3), 1059–1069.

Presenting Author

Wenxin Su

Poster Authors

Wenxin Su

PhD student

University of Essex

Lead Author

Zhou Lili

School of Psychology, Shanghai University of Sport

Lead Author

Topics

  • Assessment and Diagnosis