Savvides 2014.

Study characteristics
Methods	Study design: RCT Location: Cyprus Setting: high schools and universities Recruitment: from the cafeterias and psychology classes of the universities and through the Ministry of Education and head teachers of the schools Study dates: not reported
Participants	N = 165 Specialist population?: young adults Definition of smoker used: ≥ 1 cpd Participant characteristics: 65% female; average age: 22 years; 32% weekly allowance/income < EUR 50; average cpd: 9; average FTND score: 3.1
Interventions	Comparator: waitlist Intensity: none Pharmacotherapy: none Intervention: avatar‐led, internet‐based, ACT Mode of delivery: online Intensity: 6 sessions (x 25 min) spaced out over a minimum of 3 days between each session Pharmacotherapy: none BCTs: 1.1 Goal setting (behaviour), 1.2 Problem solving, 1.5 Review behavioural goals, 1.9 Commitment, 10.3 Non‐specific reward, 11.2 Reducing negative emotions, 12.3 Avoidance/Reducing exposure to cues for the behaviour, 12.6 Body changes, 13.4 Valued self‐identity
Outcomes	Definition of abstinence: 30‐day point prevalence Longest follow‐up: 12 months Biochemical verification: none Other relevant outcomes reported: none
Notes	Notes: quitting outcomes were collected but not reported Funding source: not reported Author conflicts of interest: not reported
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Quote: "Group assignment was done using an online random number generator"
Allocation concealment (selection bias)	Unclear risk	Quote: "Group assignment was done using an online random number generator" However, it is unclear if this was sufficient to conceal allocation.
Blinding of outcome assessment (detection bias) All outcomes	High risk	Biochemical validation not used and unequal levels of contact between study arms
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	Attrition at 12‐month follow‐up not reported
Selective reporting (reporting bias)	Unclear risk	No protocol available
Other bias	High risk	Waitlist control ‐ participants in the control arm may have delayed quitting, knowing that they would be receiving an intervention at a later date. This has the potential to inflate the reported effect of the intervention.