A bidirectional relationship between epilepsy and psychiatric disorders suggests a possible shared underlying predisposition for the conditions.
BOSTON—Psychiatric disorders are associated with an increased risk for developing epilepsy and vice versa, researchers reported at the 63rd Annual Meeting of the American Epilepsy Society. Similar associations were not found for other disorders, such as acute surgery or eczema, suggesting a possible common underlying pathology between psychiatric disorders and epilepsy, the study authors concluded.
In a matched longitudinal cohort study using information from the General Practice Research Database (GPRD), which includes 6.4 million patients in the United Kingdom, Dale Hesdorffer, PhD, of the Gertrude H. Sergievsky Center and Department of Epidemiology, Columbia University, New York City, and colleagues studied 3,217 subjects with epilepsy and 12,020 case-matched controls who were enrolled in the GPRD for approximately 13 years and found that the incident rate ratios (IRR) for depression, bipolar disorder, psychosis (including schizophrenia), and suicide attempt increased significantly in the three years before and after epilepsy onset. Cases and controls had a median age of 37; 50% were male.
For all three years before the onset of epilepsy, the IRR for new-onset psychosis, bipolar disorder, and depression was statistically significantly increased in epilepsy versus controls. In the three years after epilepsy onset, epilepsy was associated with a significant increased risk for these same disorders. The largest IRRs were observed for bipolar disorder, psychosis, and schizophrenia—both before and after epilepsy onset—and the IRR for psychosis was dramatically increased before epilepsy onset.
For suicide attempt, the IRR was increased for all three years before epilepsy onset. “After epilepsy onset, the incidence of suicide attempt was increased only in the first year, after which there was no difference between people with epilepsy and controls,” Dr. Hesdorffer told Neurology Reviews. “This suggests that epilepsy treatment may reduce or ameliorate the suicide risk.”
The IRR for eczema was not statistically significant before epilepsy onset, but increased in the year following diagnosis, which researchers attribute to potential antiepileptic drug reactions. The IRR was not significantly increased for acute surgeries before or after epilepsy onset.
In additional analyses focusing on idiopathic and cryptogenic epilepsy, investigators “observed the same magnitude and pattern of the increased IRR for each incident psychiatric disorder before and after epilepsy onset.” They noted that more research is needed to understand the shared pathophysiology of these conditions.
“These findings further emphasize the need for epileptologists to evaluate all patients with new-onset epilepsy for antecedent psychiatric disturbances and to monitor existing patients for new psychiatric disturbances,” stated Dr. Hesdorffer. “These are important for comprehensive management of people with epilepsy, and might also direct specific treatments.”
—Rebecca K. Abma