Cortisol and symptoms in bipolar disorder and schizophrenia

Abstract

Background: Dysregulation of the cortisol system may be important in the pathophysiology of severe mental disorders. In schizophrenia cortisol has been related to disorganized, negative and positive symptoms, but there are few studies in bipolar disorder. The aim of the present study was to investigate the relationship between cortisol and symptoms across diagnoses. Methods: We included patients with schizophrenia, schizoaffective disorder and schizophreniform disorder (Schizophrenia group, N=47), and bipolar 1, 2 and NOS disorders (Bipolar group, N=56), and evaluated symptoms with Inventory of Depressive Symptomatology, Young Mania Rating Scale and Positive and Negative Syndrome Scale. Morning salivary cortisol was sampled before and after a 1-2 hour session including blood sampling and neuropsychological testing. Correlations were made using Spearman’s rho. Results: Based on preliminary data, the diagnostic groups showed no correlations between cortisol and total scores of either of the symptom scales. Specific items relevant to the literature were further selected. Bipolar group: cortisol correlated negatively with conceptual disorganization (p=0.040) at baseline. Difficulty in abstract thinking and total score of negative subscale correlated positively with cortisol (p=0.046 and p=0.023 respectively) at second sampling. Schizophrenia group: mood (anxious) and mood (sad) correlated positively with cortisol at baseline (p=0.022 and p=0.005 respectively), whereas lack of spontaneity & flow of conversation (p=0.010) and cortisol correlated positively at second sampling. Conclusion: The present data suggest a correlation between severity of specific symptoms and the activity of the cortisol system in patients with bipolar disorder and schizophrenia. These symptoms might differ across the diagnostic categories.