Treatment of the Interictal Psychoses

Background: The interictal “schizophrenia-like” psychoses of epilepsy conventionally are treated with antipsychotic medication with uncertain results. In patients with these psychoses, a preceding and concomitant dysphoric disorder usually can be documented. Effectiveness of the pharmacologic treatment by the combination of drugs that is effective for severe interictal dysphoric disorders is demonstrated in a series of patients with interictal psychosis.

Method: Patients were treated with the combination of a tricyclic antidepressant and a selective serotonin reuptake inhibitor, enhanced if necessary by a small amount of the atypical neuroleptic risperidone. The series consisted of 8 consecutive patients with interictal psychosis seen over a 20-month period. Two additional patients seen over the past 10 years who required a different therapeutic intervention were also included.

Results: Five of the 8 consecutive patients achieved full remission of their psychosis; 3 patients could not be reached for the full treatment effort. One patient with a malignant psychosis had been treated successfully (prior to the series reported) by surgical removal of a left frontal epileptogenic zone; a second patient (treated after the series) recovered only upon elimination of the antiepileptic drug that had suppressed clinical seizures but had resulted in an alternating psychosis.

Conclusion: Interictal psychoses can be viewed as severe interictal dysphoric disorders with psychotic features. The same combination of psychotropic medication that is effective for severe interictal dysphoric disorders serves as the primary therapy for interictal psychoses. The interictal psychiatric disorders presumably result from seizure-suppressing mechanisms that are the targets of the proconvulsant drugs. Upon suppression of seizures, some patients with interictal psychosis may require modification of the antiepileptic medication responsible for excessive inhibition. Complete surgical removal of the epileptogenic zone can eliminate a chronic interictal psychosis upon postoperative fading of inhibitory mechanisms.