EEG evidence of epileptiform paroxysms in rapid cycling bipolar patients

Electroencephalographic (EEG) abnormalities have been described in patients with mood disorders. In an effort to determine if rapid cycling bipolar affective disorder patients may demonstrate more prevalent EEG paroxysmal activity than patients with non-rapid cycling mood disorders, we studied five consecutively identified bipolar patients who cycled at least four times a year. They were compared with 25 consecutive affective disorder patients who received an EEG before electroconvulsive therapy. Three of the five rapid cycling patients had bitemporal paroxysmal sharp waves as demonstrated by EEG but no psychomotor evidence of epilepsy. None of the 25 comparison patients had EEG abnormalities. Four of the five rapid cyclers reported a family history of affective disorder, including the three who had paroxysms.