Inter-ictal and post-ictal psychoses in frontal lobe epilepsy: A retrospective comparison with psychoses in temporal lobe epilepsy

There have been few studies of the psychopathology of patients with frontal lobe epilepsy (FLE). The majority of studies of both inter-ictal and post-ictal psychoses have strongly suggested the influence of temporal lobe disturbance on psychoses. Patients with organic brain damage or schizophrenia, however, sometimes show frontal lobe dysfunction. The purpose of this study was to better understand the effect, if any, of frontal lobe disturbance and seizure on psychopathology. Patients were divided into four groups based on epilepsy type and preceding seizures; 8 with FLE/inter-ictal psychosis, 3 with FLE/post-ictal psychosis, 29 with temporal lobe epilepsy (TLE)/inter-ictal psychosis, and 8 with TLE/post-ictal psychosis. Psychopathologic symptoms were retrospectively reviewed based on case notes, using a modified brief psychiatric rating scale (BPRS). Psychomotor excitement, hostility, suspiciousness, and hallucinatory behaviour were prominent features in all four groups. Six orthogonal factors were derived by factor analysis from the original data based on the 18 BPRS items. FLE patients with inter-ictal psychosis showed marked hebephrenic characteristics (i.e. emotional withdrawal and blunted effect). Our findings suggest that patients with FLE can exhibit various psychiatric symptoms. However, their psychotic symptoms, hebephrenic symptoms in particular, may often be overlooked.