Progression of postictal to interictal psychosis

To describe a case series of patients with both postictal psychosis (PIP) and chronic interictal psychosis (IIP).

We retrospectively reviewed the records of 43 patients with PIP from a comprehensive epilepsy center to find evidence of both PIP and IIP in the same patient.

Six (13.9%) of the 43 patients met all the criteria for both PIP and IIP. Five of our six patients had multiple documented PIPs before they became chronically psychotic. The range of length of time between PIP and IIP was 7 to 96 months. Postictal and interictal psychotic behavior was similar or identical in five of six cases.

The results of this study suggest a progression from PIP to IIP: there is a similarity between the symptoms of the two psychoses, a history of multiple PIPs before the first IIP, and a period of months to years between PIP and IIP onset.