Yawning and cortisol levels in multiple sclerosis: Potential new diagnostic tool

Abstract

Yawning is a significant behavioural response and, together with cortisol, is potentially a new diagnostic marker of neurological diseases. Evidence of an association between yawning and cortisol was found which supports the Thompson Cortisol Hypothesis and thermoregulation hypotheses, indication that brain cooling occurs when yawning. 117 volunteers aged 18–69 years were randomly allocated to experimentally controlled conditions to provoke yawning. Thirty-three had been diagnosed with multiple sclerosis. Saliva cortisol samples were collected before and after yawning or after stimuli presentation in the absence of yawning. Hospital Anxiety and Depression Scale, General Health Questionnaire, demographic and health details were collected. Comparisons were made of yawners and non-yawners, healthy volunteers and MS participants. Exclusion criteria: chronic fatigue, diabetes, fibromyalgia, heart condition, high blood pressure, hormone replacement therapy, stroke. Yawners had significant differences between saliva cortisol sample 1 and 2 among healthy participants (p < .007) and MS participants (p < .003). There was significant difference between the healthy versus MS non-yawners (P < .042) but not between yawners (p < .862). These results support the Thompson Cortisol Hypothesis suggesting that cortisol levels are elevated during yawning. Furthermore, this evidence suggests cortisol levels in the MS participants (non-yawners) are significantly different to those of healthy participants. Changes in cortisol levels may be similar in healthy and MS participants but when associated with observations of excessive yawning may become a new diagnostic tool in the early diagnosis of neurological symptoms. DRYAD DOI: https://doi.org/10.5061/dryad.r09m1.