In a rat model of treatment-resistant depression (Wistar-Kyoto rats exposed to chronic mild stress), brain scans revealed metabolic and structural changes distinct from non-depressed controls. Magnetic resonance spectroscopy showed reduced glutamate, glutamine, and taurine in the prefrontal cortex and decreased glutamine and choline compounds in the hippocampus, along with increased myo-inositol in the prefrontal cortex. Diffusion tensor imaging indicated higher mean diffusivity in both regions, consistent with demyelination or axonal loss, and lower fractional anisotropy in the hippocampus, suggesting compromised white-matter integrity. These findings mirror depression- and stress-related brain changes in humans, supporting the model's use for testing novel treatments like rTMS and psychedelics.
Anomalous self-experiences (ASEs), disturbances in the sense of a minimal self, are considered a core feature of primary psychotic disorders (PPDs) like schizophrenia, but it was unclear whether they also occur in substance-induced psychosis (SIP). This study compared ASEs in 27 clinically stable patients with schizophrenia spectrum disorders (SSD, mean age ~27) and 27 with SIP (mean age ~28) using the EASE interview. Total ASE scores did not differ between groups. However, SIP patients showed significantly higher disturbances in self-world boundary (Domain 4), while SSD patients trended higher in self-awareness and presence (Domain 2) and existential reorientation (Domain 5). These findings suggest ASEs are not exclusive to primary psychoses and challenge the assumption that self-disorders are unique to endogenous psychosis.