Intellectual disability and psychotic disorders of adult epilepsy.
OBJECTIVE
To investigate the prevalence, psychopathology, and cognitive functions associated with psychotic disorders among adult epilepsy patients with intellectual disability (ID) based on a multicenter study in Japan.


METHODS
The study was divided into three phases: a prevalence study of psychotic disorders among new referrals of epilepsy, a polydiagnostic comparative study of patients with psychotic epilepsy and those with schizophrenia, and a neuropsychological study of patients with psychotic epilepsy and education level-matched controls.


RESULTS
Among 336 new referrals of epilepsy, a higher prevalence of psychotic disorders was found among patients with ID (24%) than among those with normal intelligence (6%). The psychotic symptoms and operational diagnoses of psychotic epilepsy patients with ID were similar to those of patients with normal intelligence. A wide range (7-86%) of psychotic epilepsy patients was diagnosed as having schizophrenia, depending on the operational criteria used. Patients with psychotic epilepsy had more disturbances in verbal memory and attention functions than controls.


CONCLUSIONS
Epilepsy patients with ID show a predisposition to develop psychotic disorders. Distinguishing their psychotic symptoms from those of schizophrenia is difficult. Subtle cognitive disturbances predispose to psychotic disorders in epilepsy.
Matsuura
Masato
M
Department of Neuropsychiatry, Nihon University School of Medicine, Tokyo, Japan. matsu.mtec@tmd.ac.jp
Adachi
Naoto
N
Muramatsu
Reimi
R
Kato
Masaaki
M
Onuma
Teiichi
T
Okubo
Yoshiro
Y
Oana
Yasunori
Y
Hara
Tsunekatsu
T
D000328:Adult; D000367:Age Factors; D003072:Cognition Disorders / Q000175:diagnosis* / Q000453:epidemiology / Q000523:psychology; D015897:Comorbidity; D003937:Diagnosis, Differential; D004522:Educational Status; D004827:Epilepsy / Q000150:complications / Q000175:diagnosis* / Q000523:psychology; D005260:Female; D006801:Humans; D008607:Intellectual Disability / Q000175:diagnosis* / Q000453:epidemiology / Q000523:psychology; D007361:Intelligence Tests; D007564:Japan / Q000453:epidemiology; D008297:Male; D009483:Neuropsychological Tests; D015995:Prevalence; D011618:Psychotic Disorders / Q000175:diagnosis* / Q000453:epidemiology / Q000523:psychology; D012307:Risk Factors; D012559:Schizophrenia / Q000175:diagnosis; D012565:Schizophrenic Psychology