Williams 1988.
| Methods | Country: USA.
Study sites: not stated Study period: not stated. Recruitment: via the newsletters of three manufacturers in Northeastern Pennsylvania, USA. Sample size calculation: not mentioned. |
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| Participants | Number of participants: 60 smokers (20 in each group). Inclusion criteria: smokers who had attended at least one other smoking cessation programme, and who worked for one of 3 companies. Exclusion criteria: not stated. Overall demographics: 31 male (51.7%), ages 21 to 58, smoked an average of 36.4 CPD over an average of 5.32 years and had attended at least one other smoking cessation programme. | |
| Interventions | a) Hypnosis ‐ single 2.5‐hour group session using an adaptation of Spiegel (1970) and Stanton (1978) procedure. There were two 45‐min hypnosis trials, followed by a 45 min question period to help subjects understand procedure, alleviate misconceptions and clarify self‐monitoring procedure + post‐hypnotic suggestion to take away b) Placebo control ‐ single 2.5‐hour group discussion of reasons for smoking and attempts to quit. c) No treatment control ‐ received instructions on self monitoring and 12‐month waiting list. Duration of intervention: 2.5 hours. Duration of follow‐up: 48 weeks (12 months). | |
| Outcomes | Definition of smoking cessation: point prevalence abstinence at 48 weeks Adverse events: no information provided on whether or not AE data were collected and whether any AEs occurred. | |
| Notes | Funding: participants were told that their companies were sponsoring the programme in the interest of employees' health Author declaration of interest: not reported |
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| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| Random sequence generation (selection bias) | Unclear risk | Randomized, method not stated |
| Allocation concealment (selection bias) | Unclear risk | No details given |
| Blinding of outcome assessment (detection bias) All outcomes | High risk | Blinding not possible due to nature of intervention, self‐report only |
| Incomplete outcome data (attrition bias) All outcomes | Low risk | No missing outcome data |
| Selective reporting (reporting bias) | Low risk | All outcomes reported as described in the methods section |
| Other bias | High risk | Waiting list control; control group aware they would later receive intervention which may have discouraged quitting in this arm. |
AE: adverse events CO: carbon monoxide CPD: cigarettes per day FTND: Fagerstrom Test for Nicotine Dependence ITT: intention to tream LTFU: lost to follow‐up NRT: nicotine replacement therapy ppm: parts per million PTSD: post‐traumatic stress disorder RCT: randomized controlled trial TQD: target quit date