Mechanisms underlying how AEDs' affect behavior
The mechanisms by which AEDs affect behavior are not well understood. They may affect behavior through actions that suppress seizures, such as increased GABA activity, (activity of the neurotransmitter GABA, the main inhibitory neurotransmitter in the brain)inhibition of fast-conducting sodium channels, or both. Sedative AEDs often possess anxiolytic, antimanic, and hypnotic efficacy but can impair energy level and attention and depress mood (9). Agents that enhance GABA activity include barbiturates, benzodiazepines, valproate, gabapentin, tiagabine, and vigabatrin. Activating AEDs (e.g., felbamate and lamotrigine) paradoxically reduce excitatory neurotransmission. These drugs may possess antidepressant and attention-enhancing efficacy (10) but can cause anxiety, insomnia, and agitation. Some AEDs have both inhibitory and excitatory properties (e.g., topiramate, levetiracetam, and zonisamide) and tend to be more sedating than activating, but can also cause anxiety, irritability, and depression.