Pathways to schizophrenia: Divergent effects of childhood trauma and polygenic risk on cognition and subcortical dynamics
Abstract Background Schizophrenia is often a persistent mental illness characterized by cognitive deficits and altered brain network dynamics especially affecting the cortico-subcortical salience processing system. Childhood trauma has been implicated in mechanisms contributing to schizophrenia, but the role of genetic vulnerability remains unclear. Methods A total of 164 schizophrenia patients and 114 healthy controls were included. First, a matched subsample of 117 patients (76 with and 41 without childhood trauma), and 59 healthy controls were compared on polygenic risk scores for schizophrenia (SczPRS). SczPRS was then correlated with neurocognitive performance using a comprehensive cognitive battery (n = 147 patients) and brain-wide static and dynamic functional connectivity (sFC and dFC) using resting-state fMRI (n = 117 patients). Patients were also stratified into high-SczPRS and low-SczPRS (n = 25 each) subgroups. Results Patients with childhood trauma had significantly lower SczPRS than those without. Higher Childhood Trauma Questionnaire (CTQ) scores related to lower cognitive PC score (r = −0.282, p < 0.001), but CTQ did not affect brain-wide dysconnectivity or subcortical/salience system among patients. Patients with the highest SczPRS showed lower dFC between the cingulo-opercular network and subcortical networks (F = 7.949, p = 0.007), but SczPRS did not affect cognitive performance. Conclusions Our findings reveal distinct effects of childhood trauma and polygenic risk in the neural and cognitive substrates of schizophrenia. Childhood trauma relates to poor cognitive function, while polygenic risk primarily affects salience/subcortical network dynamics. These patterns indicate that in genetically predisposed individuals who experience childhood trauma, a “double mechanistic hit” may influence the schizophrenia phenotype.