Adjunctive lamotrigine for refractory epilepsy in adolescents with mental retardation.

Epilepsy is a major comorbid condition in adolescents with mental retardation and is often characterized by multiple seizure types that are refractory to treatment. This study (n = 22) describes a subanalysis of data from a larger multicenter study of adjunctive lamotrigine therapy in patients with mental retardation and refractory epilepsy and focuses on the outcome measures of seizure reduction, safety and tolerability, and impact on behaviors in adolescents with mental retardation and refractory epilepsy. The study kept baseline antiepileptic drugs constant and titrated lamotrigine over 8 weeks to the target dose, followed by an 8-week maintenance phase and then a 12-week optimization phase during which all antiepileptic drugs and lamotrigine could be altered as clinically indicated. Sixty percent of subjects had a 50% decrease in seizures by the end of the maintenance phase and a mean 39% reduction in seizure frequency by the end of the maintenance phase (25% by end of study) compared with baseline. Global improvements were observed in most patients, with statistically significant improvements in the Aberrant Behavior Checklist and the Habilitative Improvement Scale, which is predictive of less need for supportive care in activities of daily living and thus enhanced potential for greater independence. Lamotrigine-associated improvements in behavior can be attributed to improved control of seizures, a reduction in concomitant antiepileptic drugs, and/or direct mood-stabilizing and behavior-enhancing properties independent of the antiseizure effects of the drug. The results of this study suggest that lamotrigine is an important treatment option in adolescents with mental retardation and comorbid epilepsy.