Ng 2011.

Methods	Double‐blind, placebo‐controlled RCT
Participants	Total randomised: 238 patients with Lennox‐Gastaut syndrome; 177 participants completed the study Age range: 2 to 54 years; mean age: 12.4 years Approximately half of all participants were receiving concomitant valproic acid, valproate semisodium or valproate sodium
Interventions	Placebo Low‐dose clobazam (0.25 mg/kg/day; maximum 10 mg/day) Medium‐dose clobazam (0.5 mg/kg/day; maximum 20 mg/day) High‐dose clobazam (1.0 mg/kg/day; maximum 40 mg/day)
Outcomes	Baseline period: 4 weeks, treatment period 12 weeks. Outcomes assessed at week 4 and week 16 8‐item quality of life (QOL) questionnaire % decrease in weekly seizure frequency; overall seizure frequency Wechsler Adult Intelligence Scale (WAIS); Wechsler Intelligence Scale for Children (WISC)
Notes	217 participants were included in the analysis. Modified intention‐to‐treat analysis excluded 21 patients who did not have one or more daily seizures measurement in the 12‐week maintenance period
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Central randomisation via interactive voice
Allocation concealment (selection bias)	Low risk	Central randomisation via interactive voice
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	Although it states the trial was double‐blind there is insufficient information about how blinding was achieved
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Although it states the trial was double‐blind there is insufficient information about how blinding was achieved
Incomplete outcome data (attrition bias) All outcomes	Low risk	High attrition rate. Modified intention‐to‐treat analysis carried out
Selective reporting (reporting bias)	Unclear risk	Protocol unavailable
Other bias	High risk	Researchers were employed by pharmaceutical companies