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.

Background and Purpose-The study aimed to assess whether onset headache is an ominous sign in patients with first-ever ischemic stroke. Methods-A large population of ischemic stroke patients was obtained from the Taiwan Stroke Registry. Stroke subtypes were classified by the Trial of ORG 10172 in Acute Stroke Treatment (TOAST) criteria. On the basis of the International Classification of Headache Disorders, second version, onset headache was defined as a new headache that developed at the onset of ischemic stroke. Clinical features and impact on stroke outcomes, including in-hospital stroke in evolution, changes in National Institutes of Health Stroke Scale on discharge, and Barthel index and modified Rankin scale ≤6 months after stroke were compared between those with and without onset headache. Results-Among 11 523 patients with first-ever ischemic stroke, 848 had onset headache (7.4%). Patients with specific cause, large-artery atherosclerosis, or cardioembolism were more likely to have onset headache. Patients with onset headache were younger, predominantly female, and more likely to have posterior circulation ischemic lesions. Compared with patients without onset headache, those with onset headache had a lower frequency of stroke in evolution (4.5% versus 6.7%; adjusted relative risk, 0.64; 95% confidence interval, 0. after stroke onset). [6][7][8][9][10][11][12] Most previous studies do not specify these differences and as such, the frequencies of stroke-related headache vary from 8% to 34%. [1][2][3][4][8][9][10][11][12][13][14][15][16][17][18] In fact, stroke-related headache at different time points may result from different mechanisms and may have varying clinical effects. A large sample of patients with stroke-related headache in a well-defined time frame and a systematic follow-up of clinical features and outcomes are required to delineate the clinical impact of stroke-related headaches. The present study sought to investigate the prevalence of onset headache in patients with first-ever ischemic stroke and assess its clinical significance using a nationwide prospective registration of stroke patients. Methods Data SourceThe Taiwan Stroke Registry (TSR) was a government-funded project that identified acute stroke admissions. Formally launched on August 1, 2006, it involved 39 academic and community hospitals diffusely covering the entire country, with 4 steps of quality control to ensure the reliability of entered data. All data were compiled prospectively by TSR-trained neurologists and study nurses, and all enrolled patients were visited by physiatrists, who started rehabilitation within 72 hours after admission. More than 42 000 patients with stroke were registered when the present study was undertaken. Approval of TSR as a human study protocol was obtained from the institutional review board of each participating hospital, and all subjects provided signed informed consents and permission for follow-up.The data collection, quality-assurance processes, and preliminary results of the stroke patient...