Schachter 1995.

Methods	Randomised, double‐blind, parallel‐group study. Two treatment arms: 1 placebo, 1 lamotrigine. Patients were randomised to lamotrigine or placebo in a ratio of 3:1. Pre‐randomisation baseline = 4 weeks. Treatment phase = 24 weeks. Taper and follow‐up = 3 weeks.
Participants	A 34 centre US study with 446 participants with refractory drug‐resistant partial seizures: 334 were randomised to lamotrigine and 112 to placebo. There were 236 men and 210 women. The mean age was 35 years (range 18 to 64). The mean duration of epilepsy was 21 years, median age at onset: 12 years in the lamotrigine group and 11.5 in the placebo group. Maximum number of other AEDs = 3. Concomitant valproate therapy was not permitted.
Interventions	Add‐on lamotrigine or placebo. Lamotrigine dose up to 500 mg/day.
Outcomes	(1) Withdrawals from treatment. (2) Adverse effects.
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Computer‐generated random permuted blocks.
Allocation concealment (selection bias)	Low risk	Participants were allocated by sequentially numbered, sealed packages containing either lamotrigine or placebo.
Blinding (performance bias and detection bias) All outcomes	Low risk	Neurologists, participants and parents were blinded. Investigators were blinded. Identical tablets and packaging used.
Incomplete outcome data (attrition bias)	Low risk	No participants were excluded from analysis. 73 participants withdrew from the study; 53 receiving lamotrigine and 20 receiving placebo. The reasons for exclusion were reported.
Selective reporting (reporting bias)	Low risk	All outcomes stated in methods section of paper were reported in the results. There was no protocol available to check a priori outcomes.
Other bias	Unclear risk	This study was sponsored by GlaxoSmithKline, the manufactures of LTG.