In the present investigation, the dichotic word listening performance of a sample of 25 dysphoric neuropsychiatric patients who endorsed multiple partial seizure-like symptoms was compared with that of matched samples of normal controls and patients with mood disorders who did not endorse multiple seizure-like symptoms. Eighty percent of the patients who endorsed multiple episodic phenomena failed the dichotic listening task, compared with 8% of normal controls and 28% of patients with typical mood disorders. After treatment with carbamazepine, a subsample of polysymptomatic patients manifested significantly fewer seizure-like symptoms. This clinical improvement was typically associated with markedly improved dichotic listening performance in most cases. The results are consistent with our previous hypothesis that "subclinical" electrophysiological dysfunction may severely disrupt the normal transmission and processing of auditory information. Because it is sensitive to this type of presumed cerebral dysfunction and relatively specific, impaired dichotic listening performance is likely to be a useful clinical marker for this complex neuropsychiatric syndrome.