Crawford 2001.

Methods	Open‐label, parallel RCT
Participants	Total randomised: 83 All patients were 12 years and over. Age range = 15 to 59. All patients had intellectual disability All patients were taking 1 to 3 other AEDs Baseline period = 8 weeks. Titration period up to 14 weeks. Treatment period = minimum of 10 weeks
Interventions	Gabapentin versus lamotrigine
Outcomes	Primary efficacy = reduction in seizure frequency between baseline period and the last 8 weeks of the treatment period assessed using the R‐ratio=(T‐B)/(T+B) where T and B are the seizure frequencies per 28 days during treatment and baseline, respectively Secondary = responders (seizure frequency reduced by 50% or more. Non‐responders = seizure frequency reduced by less than 50% and those withdrawing Mood, behaviour and dependency were assessed
Notes	—
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	High risk	Participants were sequentially randomised in blocks
Allocation concealment (selection bias)	Unclear risk	Insufficient information
Blinding of participants and personnel (performance bias) All outcomes	High risk	Participants were unblinded
Blinding of outcome assessment (detection bias) All outcomes	High risk	Outcome assessment unblinded
Incomplete outcome data (attrition bias) All outcomes	Low risk	Although missing data and study attrition are unclear, an intention‐to‐treat analysis was carried out
Selective reporting (reporting bias)	Low risk	All outcomes discussed were reported. There is no evidence to suggest outcomes were selectively reported
Other bias	Unclear risk	Funded by a pharmaceutical company but no other evidence for other risk of bias