Demographic Characteristics of Patients with Epilepsy and Psychoses
Authors: Adachi Naoto , Hara Tsunekatsu , Matsuura Masato , Oana Yasunori , Okubo Yoshiro , Onuma Teiichi , Takei Noriyoshi 
Published: August 2009

Purpose: Many studies have reported that demographic characteristics are predisposing or precipitating factors for psychosts in patients with epilepsy. However, this view is still controversial because most previous studies have dealt with only small sample sizes and different diagnostic criteria. In this study, we analyzed demographic data from a large number of patients with epilepsy and psychoses and patients with schizophrenia in five major adult epilepsy clinics in Tokyo.

Methods: Epileptic psychoses were mainly defined as hallucinatory and delusional states occurring after the onset of epilepsy. Diagnoses mainly used the criteria of either organic hallucinosis, organic catatonic disorders, or organic delusional disorders of the ICD‐10 classification of mental and behavioral disorders. The patients showed no evidence of senile dementia or substance abuse. The subjects were 272 patients with epilepsy and psychoses (145 men and 127 women; mean age, 40.7 years) and 612 patients with schizophrenia of ICD‐10 (310 men and 302 women; mean age, 36.0 years) as a control group. The epileptic psychoses were divided into three subgroups: 35 postictal, 212 interictal, and 24 mixed psychoses, which developed both postictally and interictally. In this study, the following five items were evaluated: gender, age at the onset of epilepsy, type of epilepsy, age at the onset of psychosis, and duration from the first seizure to the first psychotic episode.

Results: The patients with psychoses showed a similar sex ratio over each subgroup: postictal (20 men and 15 women), interictal (112 and 110), and mixed (12 and 12). There were significant differences in the age at the onset of epilepsy between the subgroups [analysis of variance (ANOVA), p = 0.0161. Post hoc analysis disclosed that the first seizure in the postictal group occurred at a significantly later age (mean. 36.1 years) compared with those in the interictal group. Regarding the type of epilepsy, postictal psychoses were observed mostly in partial epilepsies (32/35, 91.4%). On the other hand, interictal psychoses occurred both in partial (n = 166) and generalized epilepsies (n = 36). Mixed psychoses were also observed mostly in partial epilepsies (23/24, 95.8%). Postictal psychoses occurred at age 36.1 years, which was significantly older than for the other subgroups and the schizophrenia group (ANOVA, p = 0.0001). On the other hand, there was no significant difference in duration between the age at onset of seizures and the age at onset of psychoses, although the postictal group showed a slightly longer duration.

Conclusions: Most of the patients with postictal psychoses had partial epilepsies. The mean age at the onset of postictal psychoses was significantly higher than for other groups with psychoses. These findings strongly suggest that postictal psychosis is a separate clinical entity from the other psychoses. The results are basically consistent with previous articles dealing with postictal psychoses. Furthermore, mixed psychoses are demographically similar to interictal psychoses rather than to postictal psychoses. From this point of view, patients with postictal psychosis, particularly in cases that develop during youth, may have a higher possibility of their psychoses transforming into interictal psychoses.