Yawning as Therapy? The Potential of the Conditioned Yawn Reflex as a Novel Treatment for Insomnia Disorder.

In 1986, Provine, the pioneer of yawning research wrote that 'Yawning may have the dubious distinction of being the least understood, common human behaviour' (p. 120); and so yawning remains some 40 years later, as something of a biological and social curiosity. However, this article examines contemporary scientific understanding of this age-old conundrum, proposing not only that yawning is a universal component of sleep's normal stimulus control paradigm, but that the conditioned yawn reflex might be harnessed to treat insomnia disorder. The core features of yawning as a ubiquitous, involuntary, periodic and conditionable behaviour; its associated actions on arousal, biofeedback and selective attention, as well as thermoregulation and airway patency; and its potential to signal and promote sleep engagement, lead to the proposition that the conditioned yawn reflex as therapy (CYRaT) is a feasible and potentially effective novel therapeutic for sleep-onset and sleep-maintenance insomnia disorder. Much research is required to test this hypothesis, but the article describes preliminary protocols for the administration and testing of CYRaT that might be utilised for this purpose.