Effects of carbamazepine vs valproate on cognitive functioning in patients with previously unmedicated epilepsy were evaluated in a prospective, randomized, double-blind Veterans Affairs multicenter study. Patients with seizures showed deficits relative to a normal control group prior to AED therapy. No significant decline from baseline levels of neuropsychological performance was detected over 6- or 12-month treatment intervals for either drug. Patients with high serum VPA levels (mean, 94 mcg/mL) performed less well than controls on measures of concentration and memory. Subtle compromises of cognitive functioning following treatment with VPA or CBZ were suggested by absence of practice effects. [1]

COMMENT. Carbamazepine and valproate monotherapies have subtle effects on cognitive functioning, when studies are well controlled.