Abstracts

Postictal psychosis (PIP) is an important behavioral complication of epilepsy and its early recognition is essential for appropriate management. Yet, the risk factors for PIP remain controversial. The majority of studies to date have been relatively small and have largely focused on patients with temporal lobe epilepsy (TLE). We sought to verify previous findings that correlate PIP with bilateral epileptiform interictal/ictal activity, clustering of seizures, and mesial temporal sclerosis (MTS)., We retrospectively reviewed a series of 140 patients with complex partial epilepsy undergoing video-EEG (VEEG) monitoring as candidates for epilepsy surgery. These patients were evaluated by structured neurologic and psychiatric interviews by a team of epileptologists and a single neuropsychiatrist (KA). Each patient had at least one MRI prior to surgery. No patient had psychotic symptoms at baseline. 55 of these patients were diagnosed with PIP using the criteria presented in Devinsky et al.[1], which were adapted from the definition provided by Logsdail and Toone [2]., Age, sex, age at onset of epilepsy, and history of febrile seizures were similar in the PIP and control groups. Patients with PIP experienced more generalized slowing (19.6% v 7.0% p[lt] 0.028) and more frequent seizure clusters ([gt]2 seizures in 24 hours) during VEEG monitoring (45.0% v 28.2% p[lt]0.045). Patients with PIP had more frequent clinical secondary generalization (64.7% v 43.5% p[lt]0.017), bilateral interictal epileptiform discharges (52.9% v 32.9% p[lt]0.021), and non-localized seizures (54.9% v 23.8% p[lt] 0.001) during monitoring.
MRI lesion lateralization was similar in both groups, though patients in the control group had more bilateral focal abnormalities than in the PIP group (12.3% v 4.4 p=ns). More patients in the PIP group had a nonfocal abnormality (11.8% v 2.7% p=ns). Imaging diagnosis of MTS was similar in the PIP and control groups (58.3% v 55.6% p=ns)., This retrospective study of PIP is the largest to date. PIP was more frequent in patients with electrophysiologic evidence of bilateral cortical hyperexcitability. No significant correlation was found between PIP and structural abnormalities on MRI. Although the correlation between secondary generalization and seizure clusters suggest an association with [quot]epilepsy severity,[quot] the presence of independent bilateral seizure onsets was not significant and overall baseline seizure frequency could not be formally evaluated in the population. These findings suggest PIP correlates more with neurophysiologic function than structural anatomy.
[1] Devinsky O, Abramson H, Alper K, et al: Postictal psychosis; a case control series of 20 patients and 150 controls. Epilepsy Research 1995; 20(3): 247-253.
[2] Logsdail SJ, Toone BK: Postictal psychoses: a clinical and phenomenological description. Br J Psychiatry 1988; 152:246-252.,