Schmidt 1993.

Methods	Randomised, double‐blind, cross‐over study. Two treatment arms: 1 placebo, 1 lamotrigine. Pre‐randomisation baseline not known. Treatment I and II = 12 weeks each, including 2‐week tapering period. Washout = 2 weeks .
Participants	Single centre German study. 23 adults (11 men and 12 women) with drug‐resistant partial seizures. 11 were randomised to receive lamotrigine and 12 to placebo in the initial treatment phase. Age of participants ranged from 16 to 62 years. Maximum number of other AEDs permitted was 2.
Interventions	Add‐on lamotrigine or placebo. Dosage varied from 50 mg to 450 mg (median dose was 300 mg).
Outcomes	(1) 50% responder rates. (2) Withdrawal from study for any reason. (3) 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	Unclear risk	No details provided regarding blinding of participants and parents. Unblinded investigator wrote prescriptions based on plasma concentration. Identical tablets and packaging were used.
Incomplete outcome data (attrition bias)	Low risk	No participants were excluded from analysis. 1 participant receiving lamotrigine and 9 receiving placebo withdrew from the study. The reasons for exclusion were reported.
Selective reporting (reporting bias)	Low risk	Protocol unavailable, but appears all expected and pre‐specified outcomes were reported.
Other bias	Unclear risk	This study was sponsored by GlaxoSmithKline, the manufactures of LTG.