A Comorbid Major Depression in Patients with Panic Disorder Affects the HPA Axis Response in the DEX-CRH Test

Abstract

Panic disorder (PD) has been associated with an altered reactivity of the hypothalamic-pituitary-adrenocortical (HPA) system in the dexamethasone-corticotropin-releasing-hormone (DEX-CRH) test. Recent findings showed that the duration of the PD and the severity of psychopathology are prominent moderators of the HPA-axis reactivity under hormonal stress induction. As major depression (MD) often occurs as comorbidity in patients with PD, a secondary MD might influence the reactivity of HPA-axis in the DEX-CRH test. For this study, the DEX-CRH test was implemented to observe the adreno-corticotropin-hormone (ACTH) and the cortisol release. The sample included 20 patients diagnosed with PD (mean age = 32.20 years, SD = 9.98), 20 patients with PD and comorbid MD (mean age = 37.63 years, SD = 11.31) in a Structured Clinical Interview (SCID), and 20 healthy controls (mean age = 31.97 years, SD = 10.53) matched by age and gender. The ACTH and the cortisol release increased significantly in all three groups due to the CRH injection (p < .001). The two anxiety patient groups differed in the cortisol response pattern, however, not in the ACTH. Patients with pure PD showed a lower CRH-induced cortisol release than healthy controls (p < .038) and patients with a comorbid major depression (p = .001); the latter showed the highest cortisol release in DEX-CRH test. Duration (AUCg: r = .353, p = .030; AUCi: r = .339, p = .037) and severity of psychopathology (AUCg: r = .496, p = .026; AUCi: r = .463, p = .040) significantly correlated with the cortisol release. Patients with/without comorbid MD showed some dissociation between the central and the peripheral HPA-axis functionality under the DEX-CRH test. Furthermore, it seems that a secondary depressive disorder is the decisive factor in explaining an increased reactivity of HPA-axis in patients with PD.