Bussone 1998.

Methods	Study design: randomised controlled trial Study grouping: parallel group Setting: outpatient clinic Outcome measures: State Trait Anxiety Inventory – State (STAI‐S); Pain Total Index completed at baseline, 3, 6, and 12 months
Participants	Type of chronic illness: pain (headache) Inclusion criteria: aged between 11‐15 years; satisfied the International Headache Society criteria for episodic tension‐type headache; experienced a minimum of one headache per week; neurological examination and routine laboratory tests were negative Exclusion criteria: currently or previously receiving preventative prescribed pharmacological treatment for headache Baseline characteristics Overall Number: 30 Sex (males (%)): 15 (50%) Age in years (SD): not reported Severity of chronic illness: at least 1 headache per week (moderate severity), mean headache Duration in years (SD): 2.7 (2.0) Ethnicities: not reported Anxiety symptoms ‐ rating (SD): not reported Social Skills Intervention Number: 20 Sex (males (%)): 10 (50%) Age in years (SD): 11.1 (2.6) Severity of chronic illness: at least 1 headache per week of moderate severity Duration in years (SD): 2.6 (2.0) years Anxiety symptoms ‐ rating (SD): mean state anxiety 30.1 (3.4) Anxiety symptoms ‐ category (none/subthreshold/clinical range/unsure): mild Placebo control Number: 10 Sex (males (%)): 5 (15%) Age in years (SD): 13.5 (+/‐ 1.5) Severity of chronic illness: at least 1 headache per week (moderate severity) Duration in years (SD): 2.7 (2.0) years Anxiety symptoms ‐ rating (SD): mean state anxiety 30.1 (5.1) Anxiety symptoms ‐ category (none/subthreshold/clinical range/unsure): mild Baseline differences: not described
Interventions	Intervention characteristics Biofeedback training relaxation group Audience: child Description of intervention: four sessions of progressive muscle relaxation training, lasting approximately 20 minutes per session. Six sessions of biofeedback training lasting 21 min and subjects were instructed not to practice relaxation at home in order to provide a pure test of in‐clinic treatment alone Modality: not reported Dose: 10 sessions (20 minutes each) + 4 follow‐up sessions with at least two days between any two sessions Manualised or non‐manualised: manualised Parent or caregiver involvement: not reported Therapist involvement: delivery of sessions Placebo relaxation group Description of intervention: 10 session program (2 visits per week for 5 weeks total) where participants were instructed to remain calm and attempt to relax. EMG monitoring took place throughout as per the intervention group but no feedback was given Modality: not reported Dose: 10 sessions (20 minutes each) + 4 follow‐up sessions with at least two days between any two sessions Manualised or non‐manualised: manualised Parent or caregiver involvement: not reported Therapist involvement: delivery of sessions
Outcomes	Specific anxiety measures: State Trait Anxiety Inventory – state (STAI‐S) Status of Long Term Physical Condition: Pain Total Index
Identification	Sponsorship source: Research grant from the National Institute of Neurological Disorders and Stroke, NS‐29855 Country: USA Comments: n/a Authors name: G Bussone Institution: University of West Florida Email: fandrasi@uwf.edu Address: Frank Andrasik, Behavioral Medicine Laboratory, University of West Florida, 11000 University Parkway, Pensacola,FL 32514, USA.
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Judgement comment: method of randomisation not clearly described
Allocation concealment (selection bias)	Unclear risk	Judgement comment: method of allocation concealment not described
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	Judgement comment: blinding of participants not clearly described
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Judgement comment: blinding of outcome assessors not clearly described
Incomplete outcome data (attrition bias) All outcomes	High risk	Judgement comment: 5 participants dropped out and were omitted from the analysis
Selective reporting (reporting bias)	Low risk	Judgement comment: all collected data appears to be reported.
Other bias	Low risk	Judgement comment: no other sources of bias identified