A multicenter study on the prevalence of psychiatric disorders among new referrals for epilepsy in Japan.
OBJECTIVE
To investigate the prevalence rate and risk factors of psychiatric disorders among new referrals for epilepsy, a multicenter study was conducted by using the International League Against Epilepsy (ILAE) criteria for epilepsy and the ICD-10 criteria for psychiatric disorders.


METHODS
From April 2000 to March 2001, 398 patients with epilepsy, who were referred to nine neuropsychiatric outpatient clinics specialized for epilepsy in the Tokyo metropolitan area, were evaluated by using a newly developed five-axis classification scheme.


RESULTS
Forty-two percent of the subjects showed a psychiatric disorder. Twenty-four percent of the total showed psychiatric disorders, including neurotic disorders in 8%, psychotic disorders in 7%, and affective disorders in 1%. In addition, 23% of the total showed mental retardation, and 18% showed personality disorders. A logistic regression analysis revealed that the three risk factors for a psychiatric disorder were mental retardation, temporal lobe epilepsy (as opposed to other subtypes), and a high seizure frequency.


CONCLUSIONS
The presence of mental retardation was the primary risk factor for developing a psychiatric disorder, especially a schizophrenia-spectrum disorder. The type of epilepsy alone is not a strong predictor of psychiatric illness, and intractable temporal lobe epilepsy with a high seizure frequency is accountable for the link between the epilepsy and the psychiatric illness.
Matsuura
Masato
M
Department of Neuropsychiatry, Surugadai Nihon University Hospital, Nihon University School of Medicine, Tokyo, Japan. matsuura@med.nihon-u.ac.jp
Oana
Yasunori
Y
Kato
Masaaki
M
Kawana
Akinori
A
Kan
Rumiko
R
Kubota
Humio
H
Nakano
Takashi
T
Hara
Tsunekatsu
T
Horikawa
Naoshi
N
D000293:Adolescent; D000328:Adult; D000368:Aged; D002648:Child; D015897:Comorbidity; D003430:Cross-Sectional Studies; D004827:Epilepsy / Q000175:diagnosis / Q000453:epidemiology* / Q000523:psychology; D004833:Epilepsy, Temporal Lobe / Q000175:diagnosis / Q000453:epidemiology / Q000523:psychology; D005260:Female; D006778:Hospitals, Psychiatric / Q000706:statistics & numerical data; D006785:Hospitals, University / Q000706:statistics & numerical data; D006801:Humans; D008607:Intellectual Disability / Q000175:diagnosis / Q000453:epidemiology / Q000523:psychology; D007564:Japan / Q000453:epidemiology; D016015:Logistic Models; D008297:Male; D001523:Mental Disorders / Q000175:diagnosis / Q000453:epidemiology* / Q000523:psychology; D008875:Middle Aged; D019965:Neurocognitive Disorders / Q000175:diagnosis / Q000453:epidemiology* / Q000523:psychology; D010044:Outpatient Clinics, Hospital / Q000706:statistics & numerical data; D012017:Referral and Consultation / Q000706:statistics & numerical data*; D012307:Risk Factors; D012559:Schizophrenia / Q000175:diagnosis / Q000453:epidemiology; D012565:Schizophrenic Psychology