Analogy between psychosis antedating epilepsy and epilepsy antedating psychosis.

PURPOSE: Patients with recurrent epileptic seizures after the development of psychosis (Psychosis-Epilepsy) have been regarded as belonging to a different clinical entity from those with epilepsy antedating the development of psychosis (Epilepsy-Psychosis). However, clinical characteristics of patients with Psychosis-Epilepsy have not been well described, except for early German studies. We aimed to estimate the reliability of distinction between Psychosis-Epilepsy and Epilepsy-Psychosis by comparing their clinical characteristics. METHODS: Among 312 patients with epilepsy and psychosis enrolled in this multicenter study, 23 patients had Psychosis-Epilepsy and 289 patients had Epilepsy-Psychosis (i.e., interictal psychosis). Demographic (i.e., sex, age at time of evaluation, and intellectual functioning), psychiatric (i.e., age at onset of psychosis, subtype of psychosis, duration of psychotic episode, and a family history of psychosis), and epileptic (i.e., age at onset of epilepsy, subtype of epilepsy, seizure type, and a family history of epilepsy) characteristics of both groups were compared. KEY FINDINGS: Clinical characteristics, either in their psychoses or epilepsies, except for age-related variables, were equivalent between patients with Psychosis-Epilepsy and those with Epilepsy-Psychosis. Time intervals between onset of psychosis and that of epilepsy in the two groups showed a normal distribution curve. SIGNIFICANCE: The presence of many common features and the linear distribution of the time intervals did not fully support that Psychosis-Epilepsy and Epilepsy-Psychosis were two distinctly different entities. Among certain patients who have genetic vulnerabilities to both psychoses and seizures, psychosis may develop either antedating or postdating the development of epilepsy. These findings may suggest a necessary reconceptualization of psychoses in epilepsy.

Epileptic, organic and genetic vulnerabilities for timing of the development of interictal psychosis.

BACKGROUND: Age at the first psychotic episode and an interval between the onset of epilepsy and that of psychosis reflect developmental processes of interictal psychosis. However, factors relating to these indices remain unknown. AIMS: To identify clinical variables that are associated with the timing of the development of interictal psychosis. METHOD: In 285 adults with epilepsy with interictal psychosis, effects of epileptic (epilepsy type), organic (intellectual functioning) and genetic (family history of psychosis) variables on timing of the development of psychosis were examined. RESULTS: The mean interval between the onset of epilepsy and that of psychosis was 14.4 years. Some psychosis occurred within a few years of the first seizure. Generalised epilepsy, normal intellectual function and a positive family history of psychosis were associated with early onset of psychosis. CONCLUSIONS: Early development of interictal psychosis in people with epilepsy may reflect other individual vulnerabilities to psychosis rather than epilepsy-related damage.

Difference in age of onset of psychosis between epilepsy and schizophrenia.

To clarify the nature of psychosis development in epilepsy patients, we studied differences in age of onset of psychosis between epilepsy patients with psychosis (epilepsy-psychosis) and schizophrenia patients. Subjects were 282 patients with epilepsy-psychosis (36 postictal, 224 interictal, and 22 bimodal psychoses) and 612 schizophrenia patients. Age of onset was compared between the schizophrenia group and the whole epilepsy-psychosis group as well as its subgroups. Effects of sex and family history of psychosis on age of onset were also evaluated. Epilepsy patients developed psychosis later (mean age 30.1) than schizophrenia patients (mean age 26.6). Among epilepsy-psychosis subgroups, postictal psychosis and interictal psychosis showed a later onset than schizophrenia. In interictal psychosis, while chronic schizophrenia-like psychosis occurred at similar age compared to schizophrenia, brief episodic psychosis occurred at later age. Epilepsy-psychosis patients showed no sex difference in age of onset, whereas female schizophrenia patients showed a later onset than male schizophrenia patients. Both the epilepsy and schizophrenia patients with family history of psychosis tended to develop psychosis at an earlier age, although this did not reach statistically significant level. The findings of the study suggest that the nature of epilepsy-psychosis is not fully equivalent to that of schizophrenia.

Intellectual disability and psychotic disorders of adult epilepsy.

PURPOSE: 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.

A polydiagnostic and dimensional comparison of epileptic psychoses and schizophrenia spectrum disorders.

After establishing the validity of the Japanese version of the Operational Criteria Checklist for Psychotic Illness (OPCRIT), we applied it to 58 consecutive patients with epileptic psychoses (index group) and to age- and sex-matched controls with schizophrenia spectrum disorders (control group). Compared with the control group, the index group had a low family history of schizophrenia, high premorbid personality disorder and unemployment, abrupt or acute onset of psychosis, good recovery with single or multiple episodes, and low deterioration from a premorbid level of function. From 9% to 52% of the index group and 38% to 84% of the control group were diagnosed with schizophrenia according to the operational criteria used. The percentages of patients diagnosed with schizophrenia based on various diagnostic criteria in the two groups were similar. In the index group, a diagnosis of schizophrenia was more commonly made among patients with inter-ictal psychosis than among those with post-ictal psychosis. An exploratory factor analysis identified five factor solutions of manic, negative, depressive, vegetative, and positive symptoms. Although positive and negative factor values were lower in the index group than in the control group, the two groups shared a similar factor profile. These results indicate that the difference in symptomatology between the two groups was quantitative rather than qualitative.

A multicenter study on the prevalence of psychiatric disorders among new referrals for epilepsy in Japan.

PURPOSE: 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.

Psychoses and epilepsy: are interictal and postictal psychoses distinct clinical entities?

PURPOSE: To evaluate further the relevance of designating psychotic episodes as either postictal or interictal, we compared several biologic variables between epilepsy patients with and without psychosis. METHODS: The study subjects comprised 282 patients with psychosis (36 with postictal psychosis, 224 with interictal psychosis, and 22 with both postictal and interictal psychoses, i.e., bimodal psychosis), and 658 epilepsy patients without psychosis. The clinical characteristics of these patients were reviewed retrospectively by experienced neuropsychiatrists. Factors predicting the development of each type of psychosis were determined by serial multivariate logistic regression analyses. RESULTS: Factors that were comparable between postictal and interictal psychoses were intellectual function, family history of psychosis, epilepsy type, and the presence of complex partial seizures. In contrast, age at the onset of epilepsy and at the onset of psychosis and the presence of generalized tonic-clonic seizures differed for the three types of psychosis. Patients with bimodal psychosis showed characteristics associated with both postictal and interictal psychoses. CONCLUSIONS: This study documented conditions, including both general factors and epilepsy-related factors, common to epilepsy patients with psychosis, regardless of chronologic distinctions. Certain epileptic processes appear to have equal influence on postictal and interictal psychoses. However, some differences between postictal and interictal psychoses suggest that these chronologic descriptors are valid. Our findings confirmed that psychosis associated with epilepsy should not be defined as a single, simple condition but rather as a complex condition with several possible subcategories.

Frequency and age-related variables in interictal psychoses in localization-related epilepsies.

PURPOSE: Several studies have described that patients with temporal lobe epilepsy (TLE) develop psychoses more frequently than patients with extra-temporal localization-related epilepsy (LRE). However, few controlled studies have demonstrated an increased susceptibility to psychosis in TLE patients. As one of a series of multi-center studies on psychosis in epilepsy, we investigated whether the frequency of interictal psychosis differs between types of LRE. METHODS: We reviewed some biological characteristics of 197 PE patients with interictal psychosis and of 456 LRE patients with no history of psychosis. Type of PE was determined as TLE, frontal lobe epilepsy, parietal lobe epilepsy, occipital lobe epilepsy, and multi-lobar epilepsy/undifferentiated lobar epilepsy by clinical symptoms, EEG findings, and neuroimaging. The frequency of psychosis for each type of LRE was compared. Ages at onset of epilepsy and psychosis and the time interval between onset of each were also analyzed. RESULTS: There was no significant correlation between psychosis and epilepsy type (P=0.211). Age-related variables also failed to show any significant differences between LRE types (age at onset of epilepsy, P=0.369; age at onset of psychosis, P=0.852; the time interval, P=0.893). CONCLUSIONS: Patients with LREs as well as with TLE are susceptible to interictal psychosis. The mean ages at onset of symptoms and the interval between onset of epilepsy and onset of psychosis that we observed suggest that patients with LREs, regardless of focus, may share similar processes in the development of psychiatric symptoms.