Electroretinographic dysfunction, insulin resistance, and childhood trauma in early-course psychosis: A case-control exploratory study

Background

Electroretinographic dysfunction is observed in psychosis, with a-wave and b-wave amplitudes potentially serving as biomarkers. Insulin resistance (IR) and childhood trauma (CT) have also been associated with psychosis-spectrum disorders, particularly schizophrenia. Electroretinographic dysfunction in early-course psychosis (EP) lacks exploration. This case-control exploratory study aimed to understand electroretinographic dysfunction in EP and its relationship with IR and CT.

Methods

The study involved healthy controls (n=13) and EP individuals (n=14) and included photopic and scotopic flash-electroretinography (fERG), blood collection for IR assessment, and the Childhood Trauma Questionnaire (CTQ). Data were analyzed using SPSS v.29.0. Case-control differences across fERG conditions were explored using repeated-measures ANCOVA (3 flash conditions X 2 groups) adjusted for gender and age. Sub-analyses included Fisher’s, Mann-Whitney, partial correlations, and logistic and linear regressions.

Results

Compared to controls, EP participants showed (1) lower photopic a-wave and b-wave amplitudes, specifically in the left eye and under the P₁ condition, (2) greater odds for IR, and (3) higher CTQ scores. IR was associated with a higher CTQ score and a lower P_2b amplitude. A higher CTQ score was associated with lower P_2b amplitude in the left eye when adjusting for its interacting effect with IR.

Conclusion

These findings suggest lower photopic a-wave and b-wave amplitudes, IR, and CT are explanatory markers in EP. CT may dysregulate the hypothalamic-pituitary-adrenal axis, increasing the risk of experiencing later-life psychosis. IR might be a biomarker in psychosis, contributing to electroretinographic dysfunction and neurodegeneration of cone post-synaptic cells. Further investigations are needed.