Otto 2008.

Study characteristics
Methods	Design: cross‐over Duration: 5 weeks Assessment: baseline and post‐intervention Country: Denmark
Participants	Pain condition: polyneuropathy Population: adults aged 20‐80 with chronic polyneuropathy Minimum pain intensity: ≥ 4 on 0‐10 scale Inclusion criteria Symptoms of polyneuropathy within at least 6 months, diagnosis confirmed by physical examination Pain intensity ≥ 4 on 0‐10 scale Exclusion criteria Other pain conditions and severe physical comorbidities Total participants randomised: 48 Age in years (median, range): 62 (37–74) Gender: 12/48 were female Pain duration in months (median, range): 48 (8–180)
Interventions	Placebo Inert Identical appearance and matched dosing Escitalopram 20 mg SSRI Fixed dose
Outcomes	Pain intensity Sleep Mood AEs Withdrawal
Missing data methods	ITT with LOCF
Funding source	Partly pharmaceutical: Odense University Hospital The work behind this study was supported by unrestricted grants from H. Lundbeck A/S and Gruenenthal GmbH and a grant from the Danish Clinical Intervention Research Academy.
Conflicts of interest	This was an investigator‐initiated study and neither company was responsible for the creation of the study protocol, the data analysis, data interpretation, or writing of the manuscript.
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Assignment to treatment sequence was random via a computer‐generated randomisation code with a block size of 4.
Allocation concealment (selection bias)	Low risk	The randomisation plan was generated by a person in the hospital pharmacy at Odense University Hospital who was not involved in the conduct of the trial. The study drugs were packed in boxes marked with randomisation number and treatment period by the hospital pharmacy. Patients were enrolled by the investigators and, after the baseline period, numbered consecutively by the investigators and treated with the study drugs with the corresponding randomisation number. Sealed opaque envelopes with the treatment sequence for each patient for emergency situations were present at the study sites.
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Double‐blind, identical study drugs with 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	High risk	ITT with LOCF Attrition Total: 10/41 (24.4%) Placebo: 4/41 (9.8%) Escitalopram 20 mg: 6/41 (14.6%)
Selective reporting (reporting bias)	High risk	Some outcomes mentioned prospectively on clinicaltrials.gov NR e.g. different subtypes of pain and quality of life
Other bias	Low risk	No other sources of bias were identified