Objective: To investigate the levels of serum cortisol, dehydroepiandrosterone sulfate (DHEA-S), nitric oxide (NO) and adrenomedullin (AM) in schizophrenic patients. Subjects and Methods: Sixty-six male patients with chronic schizophrenia and 28 normal male subjects participated in this study. The duration of disease was 145 +/- 120 (mean +/- SD) months. Serum levels of cortisol and DHEA-S were measured by electrochemiluminescence; plasma nitrite levels as an index of NO were measured with the Griess reaction, while plasma AM concentration was measured by using high-performance liquid chromatography. Results: Patients (12.48 +/- 3.2 mu g/dl), as compared to controls (10.31 +/- 3.1 mu g/dl), had higher levels of baseline cortisol (p < 0.05). DHEA-S levels were lower in patients though this did not reach statistical significance (302 +/- 156 mu g/dl compared to control, 322 +/- 96 mu g/dl, p 1 0.05). The mean levels of plasma AM and NO in the schizophrenic group (44.33 +/- 5.07 pmol/l and 36.27 +/- 17.6 mu mol/l) were significantly higher than the levels in the control group (14.56 +/- 4.03 pmol/l and 32.54 +/- 7.14 mu mol/l; p < 0.001, p < 0.03, respectively). There was a positive association between duration of disease and cortisol/DHEA-S ratio and cortisol level. Conclusion: The data show that schizophrenia is associated with abnormal levels of cortisol, DHEA-S, NO and AM. Copyright (C) 2007 S. Karger AG, Basel.