This noninterventional single-arm study explored effectiveness and behavioral outcomes in intellectually disabled patients treated with topiramate for epilepsy. Data from 21 patients diagnosed with cerebral palsy were available for evaluation. Behavioral changes were assessed using the validated Aberrant Behavior Checklist and Matson Evaluation of Social Skills for Individuals with Severe Retardation (MESSIER) scales. Some improvement in nearly all behavioral aspects was observed under concomitant topiramate therapy; for example, the Aberrant Behavior Checklist total score changed from 33.7+/-25.8 to 25.3+/-19.1 (P=0.047). In addition, seizure frequency decreased from 16.1+/-22.2/4 weeks to 12.2+/-17.0/4 weeks (N=21, P=0.164). Fifty-two percent of the patients experienced at least 50% seizure reduction during the 24-week treatment period. The safety profile is in accordance with the current Summary of Product Characteristics of Topiramate. Two unexpected deaths were attributed to sudden unexpected death in epilepsy.