Ginsberg 1996.

Study characteristics
Methods	Design: parallel Duration: 8 weeks Assessment: baseline, 4 weeks (halfway point), post‐intervention Country: Belgium
Participants	Pain condition: fibromyalgia Population: people with fibromyalgia Minimum pain intensity: no Inclusion criteria Fibromyalgia meeting the ACR 1990 criteria History of widespread pain for at least 3 months Pain in at least 11 of 18 specific tender points Exclusion criteria Physical health comorbidities Total participants randomised: 51 Age in years (mean): 46 Gender: 38/51 were female Pain duration in years (mean): 3.2
Interventions	Placebo n = 22 (completers) Inert Identical appearance and matched dosing schedule Amitriptyline 25 mg n = 24 (completers) TCA Fixed dose with no titration
Outcomes	Pain intensity Sleep AEs Withdrawal
Missing data methods	ITT but no information regarding imputation methods given
Funding source	NR
Conflicts of interest	NR
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	No information given, just says patients were "randomised"
Allocation concealment (selection bias)	Unclear risk	Allocation procedures not specified
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	Double‐blind, identical study drugs and matched dosing
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Self‐reported outcomes from blinded participants
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	State ITT but no imputation methods reported Attrition Total: 6/51 (11.8%) Placebo: 3/25 (12.0%) Amitriptyline 25 mg: 3/26 (11.5%)
Selective reporting (reporting bias)	Unclear risk	No protocol or trial registration found
Other bias	Low risk	No other sources of bias identified