Low early morning plasma cortisol in posttraumatic stress disorder is associated with co-morbid depression but not with enhanced glucocorticoid feedback inhibition

• Published in: Psychoneuroendocrinology 2010-04, Vol.35 (3), p.442-450
• Main Authors: Vythilingam, M, Gill, J.M, Luckenbaugh, D.A, Gold, P.W, Collin, C, Bonne, O, Plumb, K, Polignano, E, West, K, Charney, D
• Format: Article
• Language: English
• Subjects: ACTH; Adolescent; Adrenocorticotropic Hormone - blood; Adult; Adult and adolescent clinical studies; Anxiety disorders. Neuroses; Arousal - physiology; Behavioral psychophysiology; Biological and medical sciences; Circadian Rhythm - physiology; Comorbidity; Cortisol; Depression; Depression - blood; Depression - complications; Depression - epidemiology; DHEA-S; Dose-Response Relationship, Drug; Endocrinology & Metabolism; Feedback, Physiological - drug effects; Feedback, Physiological - physiology; Female; Fundamental and applied biological sciences. Psychology; Glucocorticoids - administration & dosage; Glucocorticoids - pharmacology; Hormones and behavior; Humans; Hydrocortisone - blood; Male; Medical sciences; Middle Aged; Mood disorders; Post-traumatic stress disorder; Psychiatry; Psychology. Psychoanalysis. Psychiatry; Psychology. Psychophysiology; Psychopathology. Psychiatry; PTSD; Stress Disorders, Post-Traumatic - blood; Stress Disorders, Post-Traumatic - complications; Stress Disorders, Post-Traumatic - epidemiology; Up-Regulation - drug effects; Young Adult
• ISSN: 0306-4530; 1873-3360
• DOI: 10.1016/j.psyneuen.2009.08.006

Summary Background Co-morbid major depressive disorder (MDD) in individuals with posttraumatic stress disorder (PTSD) confers a more severe clinical course and is associated with distinct biologic abnormalities. Although dysregulation in the hypothalamic pituitary adrenal (HPA) axis has been well established in PTSD, the impact of commonly co-occuring MDD has received scant attention. Methods Overnight (7 p.m. to 7 a.m.) plasma cortisol, adrenocorticotropic hormone (ACTH), dehydroepiandrosterone sulphate (DHEA-S) were measured at 30 min intervals in 9 participants with PTSD with MDD (PTSD + MDD), 9 with PTSD without MDD (PTSD − MDD) and 16 non-traumatized healthy controls. A low-dose dexamethasone suppression test was administered to evaluate feedback sensitivity to glucocorticoids. Linear mixed models with body mass index (BMI) and age as covariates and Bonferroni corrected post hoc tests assessed group differences. Results Compared to healthy controls, subjects with PTSD + MDD, but not those subjects with PTSD − MDD, exhibited lower basal plasma cortisol levels between 1:30 a.m. and 3:30 a.m. and at 4:30 a.m. and 6:30 a.m. (effect size d = 0.75). Despite similar plasma ACTH levels between the three groups, the ACTH/cortisol ratio was higher in PTSD + MDD patients compared to controls. We obtained similar results when the patient and control groups were re-studied 1 week later, and when men and current smokers were excluded. Basal plasma DHEA-S levels, and cortisol and ACTH response to a low-dose dexamethasone suppression test were similar in all three groups. Conclusions Lower early morning plasma cortisol levels and a high ACTH/cortisol ratio in subjects with PTSD and co-morbid MDD may not be due to enhanced peripheral sensitivity to glucocorticoids. A central abnormality in glucocorticoid regulation could explain HPA axis dysfunction in this subgroup.