| Methods |
Design: four group parallel trial
Purpose: examine the effect of hypnosis on smoking reduction |
| Participants |
Patients: smokers
Baseline comparability: yes (number of cigarettes smoked) |
| Interventions |
Placebo: sessions of listening to illusory subliminal messages
Untreated: no sessions
Experimental:
‐sessions of hypnosis
‐sessions called 'cognitive restructuring' with procedures identical to the hypnosis group but with no mention of hypnosis and no hypnotic induction
(Co‐intervention: NS) |
| Outcomes |
Mean number of cigarettes smoked per day |
| Notes |
|
| Risk of bias |
| Bias |
Authors' judgement |
Support for judgement |
| Adequate sequence generation? |
Unclear risk |
NS |
| Allocation concealment? |
Unclear risk |
NS |
| Blinding?
Treatment provider |
High risk |
Not described as double‐blind (placebo/hypnosis) |
| Blinding?
Outcome assessor |
Unclear risk |
Not relevant as patient reported outcome |
| Incomplete outcome data addressed?
All outcomes |
High risk |
Drop‐out > 15% or NS |
| Free of selective reporting? |
Unclear risk |
No protocol available |
| Free of other bias? |
Low risk |
|
| No signs of variance inequality or skewness? |
Low risk |
No variance inequality (F‐test not statistically significant) and no skewness (1.64 standard deviations does not exceed the mean) |
| Trial size > 49? |
High risk |
N = 25 |
| Clearly concealed allocation + trial size > 49 + drop‐out max 15% |
High risk |
Trial size < 49 |
