Silver 1997.

Study characteristics
Methods	Randomised controlled trial; usual care control
Participants	365 mothers (343 following attrition) of children aged 5‐8 with a variety of ongoing health conditions (183 intervention, 182 control; following attrition, 174 intervention and 169 control).
Interventions	Parent‐to‐parent support Group meetings and individual support phone calls, using veteran parents ("lay intervenors"). Aim was for parents to attend 6 face‐to‐face meetings and receive biweekly phone calls for over 12 months. Dose was tracked and varied widely amongst participants, with fewer contacts received, but at a longer duration than was anticipated. Control condition was standard care through relevant paediatric inpatient units, primary care, and subspecialty clinics.
Outcomes	Primary Psychiatric distress, stressful life events Psychiatric symptom index: 29 item self‐report measure, rated on a 4‐point Likert scale (0= never to, 3= very often). It includes 4 sub‐scales (depression, anxiety, anger, cognitive disturbance). The items are weighted and assigned rates from 0‐3. Total scores and sub‐scales are then calculated using a formula. Scores range from 0‐100. Higher score indicates higher level of distress. Scores of 20‐100 = high symptomatology, 10‐19 = moderate, and 0‐9 = low Campagnolo 2002. Psychiatric Epidemiology Research Interview: A structured interview, including 46 life events. This measure asks the parent to identify the number of "stressful life events" which have occurred in the last year. Each stressful life event equals 1 point. The scale has a maximum total score of 46. Secondary Child health Functional status II scale. This measures appropriate behavioural functioning. Scores range from 0‐100. Higher scores indicate higher functioning. Outcomes measured at baseline and 6, 12, and 18 months following. 18 month outcomes data was used in the meta‐analysis.
Notes	Authors contacted, and provided 18 month data
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Randomisation completed 'using a preestablished randomization procedure by a member of the research team'‐‐details not specified
Allocation concealment (selection bias)	Unclear risk	Allocation concealment not reported
Blinding of participants and personnel (performance bias) All outcomes	High risk	Given that support program was described, participants would have been aware of their allocation. Personnel would have been aware due to nature of intervention
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Interviewers were blind to intervention status
Incomplete outcome data (attrition bias) All outcomes	Low risk	Reasons for attrition and attempts at follow‐up were reported clearly. ITT analyses were used
Selective reporting (reporting bias)	Low risk	Missing time points were provided by authors on request
Other bias	Low risk	Difference in baseline PSI scores was found and controlled for in subsequent analyses.