Atkinson 1999.

Study characteristics
Methods	Design: parallel Duration: 8 weeks Assessment: baseline and post‐intervention Country: USA
Participants	Pain condition: low back pain Population: adults with low back pain Minimum pain intensity: NR Inclusion criteria Aged between 21 and 65 Low back pain (at T‐6 or below) present daily for at least 6 months Exclusion criteria Comorbid physical and mental health conditions Total participants randomised: 103 Age in years (mean, SD): NR Gender: 40/103 were female Pain duration in years (mean, SD): 14.5 (11.1)
Interventions	Maprotiline 50‐150 mg n = 33 TeCA Fixed doses of 50 mg, 100 mg, or 150 mg depending on tolerability Paroxetine 10 to 30 mg n = 34 SSRI Fixed doses of 10 mg, 20 mg, or 30 mg depending on tolerability Placebo (diphenhydramine 37.5 mg) n = 36 Identical appearance and matched dosing Active placebo ‐ antihistamine
Outcomes	Pain intensity AEs Withdrawal
Missing data methods	ITT using LOCF
Funding source	Non‐pharmaceutical: funded by the United States Department of Veterans Affairs and the National Institutes of Health
Conflicts of interest	NR
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Participants were randomised using a random number table
Allocation concealment (selection bias)	Low risk	Randomisation was performed by a research pharmacist not otherwise involved in the trial
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Double‐blinded, active placebo, all capsules had identical appearance
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Self‐reported outcomes by blinded participants
Incomplete outcome data (attrition bias) All outcomes	High risk	ITT using LOCF. Unequal dropout across arms Attrition Total: 29/103 (28.2%) Maprotiline 50‐150 mg: 13/33 (39.4%) Paroxetine 10‐30 mg: 12/34 (35.3%) Placebo: 4/36 (11.1%)
Selective reporting (reporting bias)	Unclear risk	No protocol or trial registration found. Only report data for primary outcome despite collecting post‐intervention data for other outcomes
Other bias	Low risk	No other sources of bias were identified