Stice 2006.

Methods	Design: RCT Conducted by the team who developed the intervention: yes
Participants	Description: targeted Cut‐point for inclusion for indicated studies: CES‐D ≥ 20.0 What risk was basis of inclusion for selected studies: N/A Diagnostic interview to exclude those with current or previous depression: diagnostic interview undertaken and those with current depression indicated by BDI ≥ 30.0 were excluded. Those with previous episodes of depression not excluded. Baseline severity of depression: BDI: 19.9 (mild‐moderate)   Mean age: 18.4 Age range: 15 to 22 Percentage male: 30.0% Setting: school   State what psychiatric diagnoses were excluded: none Suicide risk excluded: no Parents with history of schizophrenia/bipolar disorder excluded: no   Country: USA
Interventions	Broad category: CBT (for further information on intervention components, see Table 3) Manualised: yes Online: no Name of programme: The Blues Group Number of sessions: 4 sessions Length of sessions: 60 minutes Intensity (total number of hours): 4 hours Duration of treatment period: 4 weeks Group size: 6 to 10 Delivered by: students Fidelity: not assessed Type of comparison: WL
Outcomes	Diagnosis: BDI ≥ 30.0 Name of self‐report depression measure: BDI Name of clinical report depression measure: N/A Name of anxiety measure: N/A Name of general functioning measure: N/A Assessment points: post‐intervention and 6 months (short‐term)
Notes	Author contacted for methodological detail: no Author contacted for treatment manual: yes (provided) Author contacted for outcome data: no Coding for depression severity at baseline: where baseline severity was mild to moderate as in this trial, it was rated as mild.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	No information specified
Allocation concealment (selection bias)	Unclear risk	No information specified
Blinding (performance bias and detection bias) Subjects	High risk	The nature of the trial suggests it is unlikely participants could have remained blind to the fact they were allocated to a wait‐list control group. However, without access to the participant information sheets and PLS, level of blinding cannot be ascertained.
Blinding (performance bias and detection bias) Assessors	Unclear risk	Outcomes self‐reported. Assessor blinding therefore not applicable.
Incomplete outcome data (attrition bias) All outcomes	High risk	Proportion of participants with incomplete post‐intervention self‐reported depression scores: 18.0% by 6 months Means and SDs used in meta‐analysis based on what data: observed cases Intention‐to‐treat analyses: full information maximum likelihood ratio based on expectation‐maximisation algorithm
Selective reporting (reporting bias)	Unclear risk	Protocol not available
Other bias	High risk	Trial conducted by those who developed the intervention
Implementation integrity	Unclear risk	Implementation integrity assessed: unclear if assessed Implementation integrity adequate: N/A Implementation integrity reported: N/A