Study designs of evaluations included in the review
For the assessment of clinical efficacy of hypnosis, randomised controlled trials (RCTs) were eligible for inclusion. Comparators had to be either a waiting control, or standard medical treatment with no psychotherapeutic intervention.
Specific interventions included in the review
Studies of hypnosis were eligible for inclusion. Studies were classified as either classic hypnosis (direct suggestions) or modern hypnosis (symbolism, resource use, metaphors and indirect suggestion). Studies of classic hypnosis evaluated direct suggestions for relaxation, imagination or alleviation of symptoms, and direct post-hypnotic suggestions. Studies of modern hypnosis evaluated utilisation of resources, indirect suggestions for relaxation, imagination or alleviation of symptoms, application of metaphors, and symbolisations.
Participants included in the review
Studies of patients with psychological or medical conditions were eligible for inclusion. Studies that were intended to increase performance (such as academic or athletic) were excluded. The included studies were of children or adolescents, adults, or children and adults. Most included both male and females. The patients were out-patients, in-patients, or both.
Outcomes assessed in the review
There were no specific inclusion criteria relating to the outcomes. The outcomes measured in the included studies were treatment of anxiety, somatic complaints, reduction in symptoms or adverse effects of treatments, and smoking cessation.
How were decisions on the relevance of primary studies made?
The authors did not state how the studies were selected for the review, or how many reviewers performed the selection.