Diurnal cortisol patterns of young male patients with schizophrenia

It has been suggested that schizophrenic patients are more vulnerable to stress than healthy persons, and that stressors can trigger a psychotic episode or worsen symptoms. The biological system often studied in relation to stress is the hypothalamic-pituitary-adrenal (HPA) axis, which controls the release of cortisol. We investigated whether the diurnal basal activity of the HPA axis differed between young male patients with schizophrenia and healthy controls.

Twenty-seven male patients (mean age 22 ± 5 years) and 38 healthy male control subjects (mean age 22 ± 3 years) were included in the present study. Saliva was sampled at five time points during the day: directly after awakening, 30 min thereafter, and at 12.00 hours, 16.00 hours and 22.00 hours.

The cortisol concentration decreased significantly more during the day in the patient group thanin the control group. Patients also showed a significantly decreased area under the curve with respect to the increase, again indicating that the cortisol concentrations decreased more during the day in patients than in controls. Both the morning increase and the area under the curve with respect to the increase were significantly negatively correlated with negative symptom severity.

Patients with schizophrenia showed a different daytime sensitivity of the HPA axis. Our findings further suggest that an increase in negative symptom severity is related to a decreased HPA axis sensitivity.