Zul Merali, Ph.D. Objective: This study assessed the relationship between post- traumatic stress symptoms and salivary cortisol levels after a se- vere ice storm.
Brief Report
Posttraumatic Stress Symptoms and Salivary Cortisol Levels Hymie Anisman, Ph.D. Jenna Griffiths, Ph.D. Kimberly Matheson, Ph.D. Arun V. Ravindran, Ph.D., M.D. Zul Merali, Ph.D. Objective: This study assessed the relationship between posttraumatic stress symptoms and salivary cortisol levels after a severe ice storm. Method: Posttraumatic stress symptoms (Impact of Event Scale scores) and salivary cortisol levels were determined in 115 vic-
tims of an ice storm and in 27 healthy comparison subjects 1 month and approximately 1 year after the ice storm. Results: One month after the storm, Impact of Event Scale scores for the victims (mean=20.31, SD=15.23) exceeded those of the comparison subjects (mean=5.30, SD=9.78) but were reduced approximately 1 year later (mean=14.01, SD=13.68). A quadratic relation was found to exist between Impact of Event Scale scores and cortisol levels. Conclusions: One month after the storm, cortisol levels were found to be elevated among the victims but were diminished among those with the highest Impact of Event Scale scores. This relationship was found not to exist approximately 1 year later. (Am J Psychiatry 2001; 158:1509–1511)
I
ncreasing attention has focused on hypothalamicpituitary-adrenal functioning associated with posttraumatic stress disorder (PTSD) (1). Although stressors ordinarily increase circulating cortisol levels (2), PTSD has been associated with reduced levels of plasma, urinary, and salivary cortisol (1). As PTSD is also associated with enhanced dexamethasone-induced suppression of cortisol, elevated corticotropin-releasing hormone (CRH) levels in CSF, and a blunted ACTH response to challenges with CRH (3, 4), it is likely that with a sufficiently intense or protracted trauma, enhanced negative feedback involving hypothalamic or pituitary mechanisms may culminate in reduced cortisol secretion (1, 2). Typically, analysis of cortisol levels has been conducted by comparing individuals with or without posttraumatic stress symptoms. The present investigation assessed salivary cortisol levels among individuals differentially exposed to a common stressor (a severe and debilitating ice storm) and among those who exhibited varying degrees of posttraumatic stress symptoms and determined whether disturbances in cortisol levels were evident both 1 month and approximately 1 year after the stressor occurred.
Method The victims of the ice storm were 37 men (mean age=51.10 years, SD=2.09) and 78 women (mean age=9.49 years, SD=1.50) who were recruited by means of media presentations or by referral from the volunteers (their neighbors). The individuals most affected by the ice storm came from the regions surrounding Ottawa, Canada, including farming areas and towns with populations of fewer than 10,000 people. Of this group of 115, 61 (53.0%) reported financial losses, and 92 (80.0%) reported having to leave their homes because of loss of electricity and/or water, ranging from 3 to 21 days (mean=11.27, SD=4.29). The participants experienced significant self-reported sleep disturbances and anxiety regarding their personal safety and possessions. The comparison participants were 10 men (mean age=47.50 years, SD=3.91) and Am J Psychiatry 158:9, September 2001
17 women (mean age=48.17 years, SD=3.34) residing within Ottawa who experienced only transient electrical outages (of less than 6 hours). After written informed consent was obtained, the participants completed the revised Impact of Event Scale (5) and the Mini International Neuropsychiatric Interview (6) to confirm past or present depression. Exclusion criteria included viral illness during the preceding 2 weeks or any medical disorder requiring drug treatment that may have affected glucocorticoid activity. None was using psychotropic medication. The participants provided a morning saliva sample (from 9:00 a.m. to 11:00 a.m.), using dental cotton inserted into their cheek for about 2 minutes. The saliva was extracted by centrifugation and stored at –70°C. Approximately 1 year after the storm, 80 participants were recontacted, and 77 agreed to a follow-up session. The initial Impact of Event Scale scores of those who continued in the study (mean=20.17, SD=14.12) were comparable to the scores of those who did not (mean=20.05, SD=17.56). The participants completed the Impact of Event Scale and provided a saliva sample approximately 30 minutes after awakening (before 11:00 a.m.). Salivary cortisol levels were determined in duplicate by means of a solid-phase radioimmunoassay by using iodine 125 kits obtained from ICN Biomedicals Inc. (Costa Mesa, Calif.). The intra- and extraassay variability of these kits was less than 10%. Two- (victims versus comparison subjects) by-two (1 month versus 1 year) mixed-model analyses of variance were conducted to examine differences in Impact of Event Scale scores and salivary cortisol levels. Independent t tests assessed sex differences between the victims. Effect sizes were reported as η2, indicating the proportion of variance accounted for (7). Polynomial regression analyses were used to predict cortisol levels from posttraumatic stress symptom profiles.
Results The victims had higher total Impact of Event Scale scores (mean=20.31, SD=15.23) than did the comparison subjects (mean=5.30, SD=9.78) (F=23.01, df=1, 89, p
