COMPARATIVE COGNITIVE EFFECTS OF PHENOBARBITAL, PHENYTOIN, AND VALPROATE IN HEALTHY-ADULTS

The relative effects of antiepileptic drugs (AEDs) on cognition are co ntroversial. We compared the cognitive effects of phenobarbital, pheny toin, and valproate in 59 healthy adults using a randomized, double-bl ind, incomplete-block, crossover design. Cognitive assessments were co nducted at baseline, after 1 month on each drug (two AEDs per subject) , and at two repeat baselines 11 weeks alter each AED treatment. The n europsychological battery included 12 tests, yielding 22 variables: Ch oice Reaction Time, P3 Event-Related Potential, Finger Tapping, Lafaye tte Grooved Pegboard, Selective Reminding Test, Paragraph Memory, Comp lex Figures, Symbol Digit Modalities Test, Stroop Test, Visual Serial Addition Test; Hopkins Symptom Checklist, and Profile of Mood States. More than one-half of the variables exhibited AED effects when compare d with nondrug baselines, and all three AEDs produced some untoward ef fects. Differential AED effects on cognition were present for approxim ately one-third of the variables. Phenobarbital produced the worst per formance; there was no clinically significant difference between pheny toin and valproate.