Spanos 1990.

Study characteristics
Methods	This study was carried out in a secondary care setting. This study was blinded. Intention‐to‐treat analysis was not applicable. This study was conducted in Canada.
Participants	40 participants were recruited: None dropped out. Inclusion criteria of the trial Adults Ordinary or refractory warts not specified Warts on the hands or feet
Interventions	Hypnosis versus SA (Dermacyl, aka 'Compound W' for up to 2 weeks) versus Placebo versus Nil (no intervention) The duration of the intervention was unclear.
Outcomes	Outcomes of the trial 'Loss of warts' at 6 weeks
Notes	The strength and frequency of application of SA was not reported, so there may have been inadequate treatment.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	It was stated that participants were randomly assigned, but no details were given.
Allocation concealment (selection bias)	Unclear risk	This was unclear; no details were given.
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Salicyclic acid was compared with an identical placebo. Hypnosis was compared with a waiting list control. Therefore, this was probably done.
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Quote (page 110): "...all subjects had their warts recounted by a technician who was blind to their treatment." Comment: This was assessed as 'low risk'.
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	No information is given about dropouts or reasons for dropout or loss to follow up.
Selective reporting (reporting bias)	Low risk	All outcomes were reported.