Cortisol production rate in posttraumatic stress disorder

Context: Several authors have reported the unsuspected finding of low cortisol levels (urinary, salivary, and serum) in patients with posttraumatic stress disorder (PTSD). Objective: Our objective was to assess concentrations of cortisol and its predominant metabolites, cortisol production rate (CPR), and glucocorticoid receptor (GR) binding characteristics in PTSD compared with normal subjects. Design: Matched PTSD patients and control subjects had CPR determined by a stable isotope dilution technique after infusion of deuterated cortisol. Serum cortisol, urinary cortisol, and its metabolites were measured by gas chromatography/mass spectrometry. GR binding capacity (R_o) and ligand binding affinity (K_d) were measured in mononuclear leukocytes. Setting: All subjects were tested during a 40-h admission in an inpatient clinical research center. Patients and Participants: Ten patients with PTSD were matched by age and gender with 10 controls. Outcome Measures: Statistical comparison was conducted for various measures of cortisol in PTSD patients and normal subjects. Results: No statistical difference was found in mean level or circadian pattern of cortisol secretion using serum or salivary immunoassay detection methods. Although in the normal range, urinary cortisol by immunoassay showed statistically lower values over a 24-h period in PTSD patients compared with controls. This finding was not confirmed by gas chromatography/mass spectrometry determination of cortisol or its metabolites. CPR was not statistically different between these groups. GR also showed no alteration in R_o or K_d between the groups. Conclusion: The data indicate that PTSD in the chronic and unprovoked state is not characterized by an acute biological stress response.