[Cognitive effects of antiepileptic drugs]

Traditionally it has been shown that anti epileptic drugs have side effects which cause alterations particularly in behaviour and cognition, independently from that due to the epilepsy itself. This has caused great controversy. Some studies have informed that many of these drug effects are caused by the epilepsy rather than the drugs themselves. It is possible that the drugs may cause changes in behaviour and cognition, but these also improve when the seizures are brought under control. The main problem therefore is to determine the methodology which would take these variables into account, since many studies do not follow a standard methodology: the various drugs and neuropsychological aspects are compared using a large variety of tests.

At the present time, using suitable methodology, and double blind randomized controlled trials, it has been found that the secondary effects on cognition and behaviour are not as severe as had been thought. The drug causing most alterations is phenobarbitone and some benzodiazepines, such as clonazepam, alter cognitive function to a greater degree. With the newer anti epileptic drugs improvement in cognition has been observed due to its mechanism of action and to control of the epilepsy.