Dennis 2003b.

Methods	Setting: British Columbia, Canada. Recruitment: participants recruited from a health region near Vancouver. Randomisation: RCT 2 arm. This study explicitly drew on the definition of peer support by Dennis as "the provision of emotional, appraisal and informational assistance by a created social network member who possesses experiential knowledge of a specific behaviour or stressor and similar characteristics as the target population" (Dennis 2003a). Peer training: There was a 118 page handbook that outlined professional services available for referral, definition of peer support, tips and techniques for phone support and post‐partum depression information to be used as a reference guide provided to peer volunteers.
Participants	42 mothers at high risk for post‐partum depression (PPD) according to the Edinburgh Postnatal Depression Scale (EPDS)
Interventions	Intervention group: Peer volunteers (mothers with a history of and recovery from PPD) completed a 4 hour training session. There was also a 118 page handbook that outlined professional services available for referral. Peer volunteers were asked to contact the new mother within 48 to 72 hours of randomization. Caller: Calls were made by peer supporters but timing was negotiated with the recipient and calls were made as often as the participant deemed necessary. Control group: Standard community post‐partum care.
Outcomes	Physical health outcomes: none reported. Behavioural outcomes: none reported. Psychological health outcomes: Depressive symptomatology (Edinburgh Postnatal Depression Scale (validated)), Maternal Self‐Esteem (Rosenberg Self‐Esteem Scale (validated), Child‐Care Stress (Child Care Stress Checklist (validated ‐ unpublished data), Maternal Loneliness (short version of the UCLA Loneliness Scale (validated) ‐ all self report. Social health outcomes: none reported. Impact on participants: Maternal Perception of Peer Support (Peer Support Evaluation Inventory ‐ self report (developed for use in study ‐ not validated)). Impact on participants: none reported. Impact on peer supporter: Peer Volunteer Perceptions of Peer Support ‐ self report (Peer Volunteer Experiences Questionnaire (not validated)). Method of assessing outcome measures: phone survey
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Adequate sequence generation?	Low risk	Quote: "envelopes containing randomly generated numbers. This procedure was constructed by a research assistant who was not involved in the recruitment process."
Allocation concealment?	Low risk	A ‐ Adequate. Quote: "Randomisation was achieved by using consecutively numbered, sealed, opaque envelopes.."
Blinding? Participants	Unclear risk	Unclear.
Blinding? Providers	Unclear risk	Unclear.
Blinding? Outcome assessors	Low risk	Quote: "Research assistants blind to group allocation telephoned all participants at 4 weeks post‐randomization to assess depressive symptomology and again at 8 weeks post‐randomization to assess all outcome data."
Blinding? Data analysts	Low risk	Quote: "Data were entered into a data management system by a research assistant blind to group allocation."
Incomplete outcome data addressed? All outcomes	Low risk	Quote: "an 'intention to treat' approach was used to analyse the data."
Free of selective reporting?	Low risk	All outcomes reported.