Goodkin 1990.

Study characteristics
Methods	Design: parallel Duration: 6 weeks Assessment: baseline and post‐intervention Country: USA
Participants	Pain condition: low back pain Population: adults with low back pain Minimum pain intensity: ≥ 4 on 0‐10 VAS Inclusion criteria Minmum of 1 year of back pain or 2 prior episodes low back pain of at least 2 weeks in duration with a current episode of at least 2 weeks ≥ 4 on 0‐10 pain intensity VAS Exclusion criteria ≥ 4 additional pain sites Physical and mental health comorbidities Total participants randomised: 42 Age in years (mean, SD): 53.6 (12.9) Gender: 16/42 were female Pain duration in years (mean, SD): 20.3 (16.0)
Interventions	Placebo n = 20 Inert Identical appearance and taste, and matched dosing schedule Trazodone ≤ 600 mg n = 22 SARI Forced titration to maximum tolerable dose Mean dose: 201 mg/day
Outcomes	Pain intensity Physical function Mood Withdrawal
Missing data methods	ITT with LOCF
Funding source	Partly funded by pharmaeutical: "This work was supported by NIH grants MH18764 and MH16744 and NIMH Mental Health Clinical Research Center grant MH41115, a grant from the Procter and Gamble Company, a grant from the Stanford University Health Sciences Research and Development Fund, and a grant from the Western Research and Development Office of the Veterns Administration."
Conflicts of interest	NR
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Randomisation methods not specified
Allocation concealment (selection bias)	Low risk	Participants were randomised to either trazodone or placebo groups by the Stanford University pharmacist who never interacted with participants
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Double‐blind, identical appearance of study drugs and matched dosing schedule
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Self‐reported outcomes from blinded participants
Incomplete outcome data (attrition bias) All outcomes	High risk	ITT with LOCF Attrition Total: 13/42 (31.0%) Placebo: 4/20 (20.0%) Trazodone ≤ 600 mg: 9/22 (40.9%)
Selective reporting (reporting bias)	Unclear risk	No protocol or trial registration found
Other bias	Low risk	No other sources of bias were identified.