Prior to the development of symptoms, patients most frequently report severe illness, surgery, accident, and/or physical and psychological or emotional trauma.22 Evidence exists that under the influence of such triggers, the condition begins with circadian rhythm dysregulation.23 A debilitating fatigue that is unlike everyday tiredness and not resolved by sleep or rest is reported, along with difficulties in memory and concentration.24 The developing sleep disorder results in daytime sleep, and the enforced rest rapidly develops into severe muscle deconditioning.25 Often described as the “payback phenomenon”, patients recount an increase in symptoms of myalgia, dizziness, and tachycardia.26 Although not fully understood, symptoms including nausea, muscle tension, and disruption to bowel and bladder function also occur. It appears that the autonomic nervous system and fight-or-flight response are more greatly activated as patients attempt to maintain their previous functional lifestyle and responsibilities levels.26 Sufferers experience a downward spiral of physical symptoms that can result in reactive anxiety and depression.27,28 Fenouillet et al29 confirms that pathogenesis appeare to be multifactorial.30