Comorbidity of migraine: the connection between migraine and epilepsy.

Although an association between migraine and epilepsy has long been discussed, it has rarely been studied systematically. According to the evidence from the large epidemiologic study reviewed in this article, individuals with epilepsy are 2.4 times more likely to develop migraine than their relatives without epilepsy. Risk of migraine is elevated in patients with partial-onset and generalized-onset seizures. The comorbidity of migraine and epilepsy may be explained by a state of neuronal hyperexcitability that increases the risk of both disorders. Clinical and EEG features useful in the differential diagnosis of migraine and epilepsy as well as in the diagnosis of both conditions when they occur concurrently are reviewed. When migraine and epilepsy occur together, therapy with agents effective for both conditions should be considered.