Evidence-based hypnotherapy for asthma: a critical review.

Asthma is a chronic disease with intermittent acute exacerbations, characterized by obstructed airways, hyper-responsiveness, and sometimes by chronic airway inflammation. Critically reviewing evidence primarily from controlled outcome studies on hypnosis for asthma shows that hypnosis is possibly efficacious for treatment of symptom severity and illness-related behaviors and is efficacious for managing emotional states that exacerbate airway obstruction. Hypnosis is also possibly efficacious for decreasing airway obstruction and stabilizing airway hyper-responsiveness in some individuals, but there is insufficient evidence that hypnosis affects asthma's inflammatory process. Promising research needs to be replicated with larger samples and better designs with careful attention paid to the types of hypnotic suggestions given. The critical issue is not so much whether it is used but how it is used. Future outcome research must address the relative contribution of expectancies, hypnotizability, hypnotic induction, and specific suggestions.