Drs. Chen and Chou contributed equally to this work.
FULL-LENGTH ORIGINAL RESEARCH
Bidirectional relation between schizophrenia and epilepsy: A population-based retrospective cohort study
Article first published online: 19 SEP 2011
Wiley Periodicals, Inc. © 2011 International League Against Epilepsy
Volume 52, Issue 11, pages 2036–2042, November 2011
How to Cite
Chang, Y.-T., Chen, P.-C., Tsai, I.-J., Sung, F.-C., Chin, Z.-N., Kuo, H.-T., Tsai, C.-H. and Chou, I.-C. (2011), Bidirectional relation between schizophrenia and epilepsy: A population-based retrospective cohort study. Epilepsia, 52: 2036–2042. doi: 10.1111/j.1528-1167.2011.03268.x
- Issue published online: 27 OCT 2011
- Article first published online: 19 SEP 2011
- Accepted August 2, 2011; Early View publication September 19, 2011.
- Bidirectional relation;
Purpose: 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.