Papeles del Psicólogo, 2009. Vol. 30(2), pp. 98-116
Hypnosis is a valuable clinical intervention for the treatment of a wide variety of psychological and medical problems which helps improve the quality of life in patients. This paper reviews the state of the evidence regarding the efficacy of hypnosis taking into account the most rigorous research results in this respect, together with other studies of clinical relevance although they do not fulfill stringent methodological criteria. Overall, the findings of research indicate that hypnosis used as an adjunctive to other medical or psychological interventions increases the efficacy and/or efficiency of these interventions. Moreover, hypnosis efficacy is well established in certain clinical applications, especially pain management and other medical conditions, and there is acceptable evidence of its efficacy in treating depression, sleep disorders, smoking cessation, obesity, asthma, and enuresis in children. According to the literature to date, continued research using randomized, controlled methodologies as well as adequate sample sizes is well justified, and it is essential in order to establish the efficacy of hypnosis in other areas.