Shared mechanisms in affective illness, epilepsy, and migraine.

For a specific subgroup of patients with migraine or affective illness who experience illness progression and drug tolerance, the amygdala kindling paradigm can be a useful, but nonhomologous, model. Although these patients do not have a seizure or seizure-like disorder, kindling has been used to examine the types of memory-like mechanisms that could underlie syndrome evolution in both migraine and affective illness. While the precipitants, symptomatology, duration of attack, and aura symptoms differ among epilepsy, migraine, and the affective disorders, all are paroxysmal dysregulations that partially share effective drug treatment. The principles of seizure progression presented here may apply to affective and migraine patients whose episodes progress from isolated and intermittent to more chronic or daily. These patients may also develop tolerance to long-term prophylactic treatments.