Bidirectional relation between schizophrenia and epilepsy: A population-based retrospective cohort study

Abstract

SUMMARYPurpose: Schizophrenia and epilepsy may share a mutual susceptibility. This study examined the bidirectional relation between the two disorders. Methods: We used claims data obtained from the Taiwan National Health Insurance database to conduct retrospective cohort analyses. Analysis 1 compared 5,195 patients with incident schizophrenia diagnosed in 1999-2008 with 20,776 controls without the disease randomly selected during the same period, frequency matched with sex and age. Analysis 2 comprised a similar method to compare 11,527 patients with newly diagnosed epilepsy with 46,032 randomly selected sex-and age-matched controls. At the end of 2008, analysis 1 measured the incidence and risk of developing epilepsy and analysis 2 measured the incidence and risk of developing schizophrenia. Key Findings: In analysis 1, the incidence of epilepsy was higher in the schizophrenia cohort than in the nonschizophrenia cohort (6.99 vs. 1.19 per 1,000 person-years) with an adjusted hazard ratio (aHR) of 5.88 [95% confidence interval (CI) 4.71-7.36] for schizophrenia patients. In analysis 2, the incidence of schizophrenia was higher in the epilepsy cohort than in the nonepilepsy comparison cohort (3.53 vs. 0.46 per 1,000 person-years) with an aHR of 7.65 (95% CI 6.04-9.69) for epilepsy patients. The effect of schizophrenia on subsequent epilepsy was greater for women, but the association between epilepsy and elevated incidence of schizophrenia was more pronounced in men. Significance: We found a strong bidirectional relation between schizophrenia and epilepsy. These two conditions may share common causes. Further studies on the mechanism are required.

Biomarkers of Epileptogenesis: Psychiatric Comorbidities (?)

“…Yet, population-based studies of primary psychiatric disorders have established that not only are PWE more likely to develop these comorbid conditions than the general population, but have also suggested that patients with "primary" psychiatric disorders are at higher risk of developing epilepsy [1][2][3][4][5][6][7]. For example, in the first study, conducted in Sweden, depressive disorders were seven times more common among patients with new-onset epilepsy, preceding the seizure disorder, than among age-and sex-matched controls [1].…”

“…Of note, the OR among depressed patients was higher for idiopathic or cryptogenic seizure disorders (3.9, 95 % CI 2.4-6.1) than for symptomatic seizures (1.5, 95 % CI 0.8-2.6). Likewise, in a population based-study conducted in Taiwan, patients with schizophrenia had a 6-fold higher risk of developing epilepsy than controls [7].…”

“…Yet, in people with epilepsy (PWE), data from epidemiologic studies have shown a higher prevalence of primary psychiatric disorders preceding the onset of the seizure disorder than in the general population [1][2][3][4][5][6]. In addition, in animal models of depression, rapid amygdala kindling was achieved more rapidly when the animal was subjected to conditions of great stress [7]. These observations have raised the question of whether psychiatric comorbidities can be "a risk" for the development of epilepsy and, if so, could we identify a biomarker for epileptogenesis among their pathogenic mechanisms.…”

Epilepsy and Psychiatric Disorders: Is There a Common Genetic Susceptibility?

“…These findings suggest that a large number of candidate CNVs are not disease-specific but are involved in the expression of different behavioural and neuropsychiatric phenotypes sharing common biological pathways, affecting glutamate and GABA neurotransmission. However, it should be stressed that the pleiotropic effect of CNVs in neuropsychiatric disorders, may be due not only to haploinsufficiency, but also to the contribution of additional genetic, epigenetic and environmental factors yet unidentified [9].…”

The relationship between schizophrenia and epilepsy: the history and current state of the problem

“…Группа ученых из Тайваньского медицинского уни-верситета [56] провела анализ базы данных Национально-го центра медицинского страхования и медицинской ста-тистики за 1998-2008 гг. Они выбрали 5195 больных ши-зофренией (по сравнению с 20 776 -без шизофрении) и 11 527 -с эпилепсией (по сравнению с 46 032 -без эпи-лепсии).…”