Tobacco usage interacts with postdisaster psychopathology on circadian salivary cortisol

Posttraumatic stress disorder (PTSD) and major depressive disorder (MDD) have been associated with increased rates of tobacco usage as well as with dysregulations of the hypothalamus-pituitary-adrenal (HPA) axis. At the same time tobacco also affects the HPA axis. This paper examines the relationships between PTSD, posttraumatic MDD, smoking and levels of circadian cortisol 2-3 years postdisaster. Subjects were survivors of the Enschede fireworks disaster. The sample consisted of 38 healthy survivors, 40 subjects with PTSD, and 17 subjects with posttraumatic MDD. The Composite International Diagnostic Interview was used to determine mental disorders in accordance with DSM-IV criteria. Salivary cortisol samples were collected at home immediately upon awakening, 30 min after awakening, at noon, and at 10 p.m. Quantity of smoking was measured through self-report. The results of the study show that salivary cortisol concentrations were higher in smoking subjects. Survivors with MDD following the disaster had a flatter diurnal cortisol curve than subjects with PTSD or healthy survivors. In survivors with PTSD and healthy individuals the usual dynamic pattern of increase in cortisol past awakening was present, while we did not observe this in posttraumatic MDD. These survivors with MDD tended to use more tobacco per day, and the cortisol group differences could only be revealed when we adjusted for quantity of smoking. Smoking, which may be an important palliative coping style in dealing with posttraumatic arousal symptoms, seems to mediate the relationship between traumatic stress and the HPA-axis.