Antiepileptic efficacy of vigabatrin in people with severe epilepsy and intellectual disability.

The short- and long-term clinical efficacy of add-on vigabatrin treatment was evaluated in a group of 36 patients with intellectual disability and drug-refractory epilepsy. The results were compared to the efficacy of vigabatrin in 75 non-retarded patients with drug-resistant complex partial and secondarily generalized seizures. After 3 months, 42% of the patients with intellectual disability had experienced a reduction in seizure frequency of more than 50% (responders). The percentage of responders was still 22% after 6 years. No impairment in psychological function was observed during vigabatrin treatment compared with baseline values. However, one patient was excluded from long-term treatment because of psychotic depression and two patients because of psychomotor slowing after 1-2 years of treatment The need for extra supervision appeared to diminish and three patients were able to be discharged from institutional care during the follow-up. In the group of non-retarded patients, the percentages of the responders were 55% and 27% after 3 months and 6 years of treatment, respectively. The results from these studies suggest that vigabatrin is effective and relatively well tolerated, and that the successful treatment of epilepsy also has socio-economic consequences in patients with intellectual disability and severe epilepsy.