Study	Reason for exclusion
Besag 1995	No randomisation.
Buoni 1999	No randomisation.
Erenberg 1982	No randomisation.
Ferrie 1995	Retrospective study.
Glauser 2017	Provides further data on the study (Glauser 2013a), previously included; these data are irrelevant to the aims of this review.
Holmes 2008	No randomisation.
Kang 2012	No patients with absence seizures included.
Nejad 2009	No patients with childhood absence seizures included.
Santavuori 1983	Retrospective study.
Schlumberger 1994	No randomisation.
Shinnar 2017	Provides further data on the study (Glauser 2013a), previously included; these data are irrelevant to the aims of this review.
Suzuki 1972	No randomisation.