EPILEPSY AND PSYCHIATRIC DISORDERS: EVIDENCE FOR A BIDIRECTIONAL RELATIONSHIP
Abstract number :
2.134
Submission category :
6. Cormorbidity (Somatic and Psychiatric)
Year :
2009
Submission ID :
9843
Source :
www.aesnet.org
Presentation date :
12/4/2009 12:00:00 AM
Published date :
Aug 26, 2009, 08:12 AM
Authors :
Dale Hesdorffer, L. Ishihara-Paul, L. Mynepalli, D. Webb, J. Weil and W. Hauser
Rationale: Most studies of the comorbidity of epilepsy and psychiatric disorders are cross-sectional in clinically select populations. In population-based studies considering time order, depression and suicidality are associated with an increased risk for developing epilepsy and epilepsy is associated with an increased risk for schizophrenia. The bidirectionality of these relationships has not been examined. We assessed whether major depression, bipolar disorder, suicide attempt, and schizophrenia have a bidirectional relationship with epilepsy. Methods: A matched, longitudinal cohort study using the General Practice Research Database (GPRD), comparing the incidence rate of psychiatric disorders among cases with incident epilepsy to that among controls. Cases, aged 10-60 years were identified by at least one epilepsy code and at least 2 antiepileptic drug prescriptions from 1 month before through 6 months after the 1st epilepsy code. Four controls without past history of epilepsy were matched to each case by year of birth, sex, and General Practice. Cases and controls had at least 3 years of records in the GPRD prior to the index date and 12 months after. GPRD medical codes were used to identify major depression, bipolar disorder, suicide attempt and schizophrenia. Diagnoses on the index date are counted in the “before index date” time period. The incidence rate ratio (IRR) was used to compare the incidence of new psychiatric disorders for each of the three years before and for each of the three years after the index date for cases vs controls. Reference comorbidities included acute surgeries (e.g., appendectomy) and eczema. Results: Among 3,019 cases with epilepsy and 11,204 controls (median GPRD follow-up >16 years for both groups), the IRR was significantly increased before and after epilepsy onset for depression, bipolar disorder, schizophrenia and suicide attempt (Table 1). For depression, the IRR was statistically significantly increased in the third and first year before and all years after epilepsy onset. For suicide attempt, the IRR was increased for all 3 years before and for the first year after epilepsy onset. The largest IRRs were observed for bipolar disorder and for schizophrenia both before and after epilepsy onset. The IRR was not statistically significant for acute surgery or eczema either before or after epilepsy onset. Additional results will be presented excluding cases with secondary causes of their seizures (e.g., stroke). Conclusions: There is a bidirectional relationship between epilepsy and these psychiatric disorders. Psychiatric disorders are associated with an increased risk for developing epilepsy and epilepsy is associated with an increased risk for developing psychiatric disorders. Similar associations are not seen for acute surgery or for eczema. Associations observed are specific to psychiatric disorders, indicating an underlying common predisposition to psychiatric disorders and epilepsy. Further work is needed to elucidate the shared pathophysiology of these disorders.
Cormorbidity