July 5, 2007 -- People with epilepsy are three times more likely to commit suicide than the general population, and women with the disease have a greater suicide risk than men, according to new research from Denmark.
The Danish study is not the first to link epilepsy to an increase in suicide, but it is the first to use a comprehensive, nationwide population registry to investigate the association.
Newly diagnosed epilepsy patients were more than five times more likely to commit suicide than patients who had been diagnosed more than six months previously. A 29-fold increase in suicide risk was seen in newly diagnosed patients with a history of psychiatric illness.
"Even when mental illness and other suicide risk factors were controlled for, people with epilepsy were at increased risk for suicide," researcher Per Sidenius, MD, of Aarhus University Hospital tells WebMD.
"It is clear that epilepsy patients need [mental health] support, especially immediately after a diagnosis of epilepsy."
Epilepsy, Depression, and Suicide
Sidenius and colleagues compared health histories of 21,169 suicide cases occurring in Demark between 1981 and 1997 to 423,128 people who had not committed suicide -- matched by sex and age. The suicide cases were taken from a comprehensive Danish death registry.
A total of 492 of the suicides occurred among people with epilepsy (2.32%), compared with 3,140 cases of epilepsy in the people who had not committed suicide (0.74%), corresponding to a threefold higher suicide risk among epilepsy patients.
When people with a history of psychiatric illness were excluded from the analysis and researchers adjusted for other risk factors associated with suicide, epilepsy patients were still twice as likely to commit suicide as people without epilepsy.
Women with epilepsy and a history of psychiatric disease were 23 times more likely to commit suicide than women without either condition, compared with a tenfold increase in risk among men with epilepsy and psychiatric illness.
The study is published in the August issue of the journal Lancet Neurology.
Sidenius says the findings point to the importance of evaluating epilepsy patients for depression and suicidal behavior and offering psychiatric treatment if needed.
"Newly diagnosed patients often have many misconceptions about the disease," he says. "They often don't understand that there are good treatments with few side effects."
Epilepsy-Suicide Relationship Complex
Depression is more common among people with epilepsy than among the general population. Certainly, the difficulties of living with seizures can cause depression, but this does not appear to fully explain the association.
People with a history of depression, for example, have been shown to have a higher risk for developing epilepsy. And most studies have failed to show a link between severity of seizures and depression symptoms.
In 2005, researchers from Columbia University reported an increased risk of suicidal thoughts and behaviors in patients who later developed epilepsy.
The finding suggests a complex relationship between suicide, seizures, and epilepsy, says Columbia's Dale C. Hesdorffer, PhD, who led the study team.
She tells WebMD that a common underlying brain dysfunction may link epilepsy and suicidal behavior.
"Patients with new-onset seizures should be thoroughly evaluated to determine if they have a history of major depression or suicidal behaviors," she says. "Our research suggests a common underlying predisposition for suicidal behavior and epilepsy that is, as yet, not understood."