Carbamazepine has been implicated in the development
of psychosis in four patients in one report2.
Only one of our five patients was on carbamazepine
at the time of topiramate treatment. One patient who
had a history of psychiatric disease was on three AEDs
including vigabatrin. Vigabatrin has been reported to
have psychosis as a side-effect1. Two other patients
were not on any AEDs when topiramate treatment was
begun. These facts suggest that a combination of topiramate
with other AEDs, implicated in the development
of psychosis in the past, may not be the sole explanation
for the development of symptoms of psychosis in our
patients. Topiramate shares a GABAergic action with
vigabatrin, gabapentin, and tiagabine, along with its
other actions as a sodium channel blocker and antiglutamatergic
activity. Vigabatrin has been reported to be
responsible for the development of psychosis along
with various other psychiatric symptoms. Gabapentin
has been reported to cause significant cognitive impairment
in children4.However, the underlying mechanism
for these side-effects is unclear.