Stress is a powerful precursor of fibromyalgia pain, but that pain does not lead to more stress, according to an ambulatory assessment study published in Psychoneuroendocrinology.1
Using electronic diaries with 6 daily check-in times, researchers from the University of Marburg, Germany, followed stress and pain in the everyday lives of 32 women living with fibromyalgia.
Over a 2-week period, participants rated their momentary stress and pain on awakening, 30 minutes after awakening, and at 11 am, 2 pm, 6 pm, and 9 pm. Saliva samples collected at each diary entry were used to measure cortisol and alpha-amylase as indicators of stress-responsive systems.
Results showed that higher momentary stress correlated with increased pain levels 3 to 4 hours later, but that the reverse was untrue — momentary pain did not predict future stress. Moreover, the stress-pain relationship was not mediated by cortisol, nor by alpha-amylase.
According to coauthor Ricarda Mewes, PhD, the findings came as a “bit of a surprise.”
“On the basis of the available cross-sectional literature and also on my experiences with patients suffering from chronic pain, I expected pain to result in stress in their everyday life,” Dr Mewes told Clinical Pain Advisor, noting the possibility that pain could instead cause emotional distress, which was not addressed in the study.
Richard Harris, PhD, a researcher from the University of Michigan in Ann Arbor, has also used electronic diaries to examine the implications of pain fluctuation in fibromyalgia patients. Though not involved in the current study, DrHarris notes that inclusion of cortisol and alpha amylase provides an interesting aspect to this type of research.
“It is one of first [studies] that gets at this issue of the relationship between stress and pain, using ecological momentary assessment coupled with cortisol and other objective measures,” Dr Harris told Clinical Pain Advisor, pointing out that real-time data is superior to that obtained via conventional diaries.