Seizures may present with ictal or interictal psychosis mimicking primary psychiatric disorders. The authors reviewed EEG, brain-imaging, and clinical data of 240 patients presenting with acute psychotic episode to assess the diagnostic value of EEG in differentiating ictal psychosis from primary psychosis. Seven patients had interictal spikes, but there were no patients with ictal discharges. There were no significant associations between the tested variables except that taking neuroleptics/antidepressants was associated with abnormal EEG, and older age and taking anti-epileptic drugs were associated with abnormal CT scans. These findings do not support routine use of EEG in patients presenting with acute psychosis.