However, because tolerance is less likely to occur for adverse behavioral effects, patients may experience higher and higher levels of sedation and cognitive disturbance as doses rise. There is no definitive evidence that ethosuximide produces cognitive changes. In fact, when untreated patients were initiated on ethosuximide, cognitive performance on psychometric tests improved in almost half the group. This may be related to control of spike-wave activity. Ethosuximide has been associated with behavioral changes and psychosis.
Most cases occur in adolescents and individuals with a prior history.
The psychosis may be acute and may be accompanied by both visual and auditory hallucinations. Less is known about the effects of the new and emerging AEDs. This discussion will be limited to the three drugs about which we know the most. Lamotrigine and vigabatrin have been available in Europe for several years, and both experiential and trial information is available. Gabapentin has been available for more than a year in the United States, and has undergone extensive evaluation in clinical trials.