Abstracts

Two prior studies in adults suggest that depression is associated with an increased risk for epilepsy. Following the diagnosis of epilepsy, some studies suggest that suicide is a more common cause of death than expected in the general population. We undertook a population-based case-control study of epilepsy in Icelandic adults and children to address whether DSM-IV diagnosis of major depression is associated with an increased risk for developing unprovoked seizures. Population surveillance was used to identify individuals with first unprovoked seizure or incident epilepsy. Age-matched controls were selected from the population registry as the next two same sex births who were alive, resided in Iceland at the time of the index seizure, and did not have a history of unprovoked seizure on the date of the case[rsquo]s incident seizure. Symptoms of major depression were ascertained, using the lifetime module of the DISC for Diagnostic and Statistical Manual IV (DSM-IV) for children [ge] 3 years, and using a standardized interview based on the SCID for adults. Odds ratios and 95% confidence intervals were obtained, using logistic regression for matched sets. 387 cases and 773 controls were enrolled. Major depression (DSM IV) prior to the onset of seizures occurred in 10.6% of cases and 6.3% of controls (OR=1.8, 95% CI=1.1-2.8). In a multivariate model, examining individual symptoms of depression suicide attempt was associated with an increased risk for epilepsy (OR=4.3, 95% CI =1.6-11.9). This increased risk remained even after controlling for major depression and bipolar disorder (adjusted OR for suicide attempt=4.2, 95% CI=1.8-9.8). The increased risk for seizures associated with suicide attempt was present for suicide attempt with depression (OR=4.2, 95% CI=1.7-10.5) and for suicide attempt without depression (OR=16.0, 95% CI=2.0-129.2). Major depression is associated with an increased risk for developing unprovoked seizures in children and adults. Coherent with some studies showing an increased risk for completed suicide following the diagnosis of epilepsy, attempted suicide is independently associated with an increased risk for developing unprovoked seizures. This is consistent with a common antecedent. Further exploration of these associations is needed. (Supported by a Grant R01 NS 32663 from the National Institutes of Neurological Disorders and Stroke)