Interaction between high interleukin-2 and high cortisol levels is associated with psychopathology in patients with chronic schizophrenia

Background: Both cortisol and interleukins appear at abnormal levels in schizophrenia. Our previous study has shown that cortisol and interleukins are associated with psychopathology and response to antipsychotic medi-cations in a relatively small sample size of patients with schizophrenia. The current study was designed to investigate how cortisol, interleukins (ILs) and their interactions would correlate with clinical presentation in a relatively large sample size of patients with schizophrenia. Methods: We compared serum cortisol, IL-2, IL-6, and IL-8 levels in 162 medicated schizophrenia patients (including 27 patients in remission) and 62 healthy controls. Serum levels of cortisol and interleukins were measured by radioimmunoassay and quantitative ELISA, respectively. Clinical symptoms were assessed ac-cording to the Positive and Negative Syndrome Scale (PANSS). Results: Patients with schizophrenia had significantly higher levels of cortisol and IL-2 compared to controls. Patients in remission had higher levels of IL-6 than non-remitting patients. PANSS positive symptoms, general psychopathology, cortisol and IL-2 were the most central nodes in the cortisol-IL-symptom network. The inter -action between cortisol and IL-2 was associated with PANSS positive symptoms, general psychopathology and depressive factor. For patients with cortisol level above the median, IL-2 was negatively associated with PANSS positive symptoms and general psychopathology. Conclusions: Our results indicated that the interaction between cytokines and cortisol may be associated with the pathophysiology of some symptoms in chronic schizophrenia. In particular, the interaction between cortisol and IL-2 is associated with the clinical phenotypes of schizophrenia.

Automated summary

In this study, cortisol and interleukins were found to be associated with clinical presentation in a relatively large sample size of schizophrenia patients. Patients with schizophrenia had significantly higher levels of cortisol and IL-2 compared to healthy controls. Additionally, higher levels of IL-6 were observed in patients in remission compared to non-remitting patients.