68 eller placebo i maksimalt 76 uger (18 måneder).
Once stabilised using lamotrigine monotherapy or adjunctive therapy, patients were randomly assigned into one of five treatment groups: lamotrigine (50, 200, 400 mg/ day), lithium (serum levels of 0.8 to 1.1 mMol/ L) or placebo for a maximum of 76 weeks (18 months).