Common mechanism may underlie epilepsy, suicidality

By Eleanor McDermid, Senior medwireNews Reporter

Patients with epilepsy have an increased risk of attempting suicide, which precedes their epilepsy diagnosis, say researchers.

They found that patients had around a twofold increased risk of a first or recurrent suicide attempt prior to being diagnosed with epilepsy.

“Thus, our findings are consistent with the hypothesis of a common underlying susceptibility to both attempting suicide and epilepsy that is not mediated by psychiatric disorders”, Dale Hesdorffer (Columbia University, New York, USA) and co-researchers write in JAMA Psychiatry.

The team used data from 14,059 patients with incident epilepsy, identified in the UK Clinical Practice Research Datalink, and 56,184 controls without epilepsy who were matched to the patients by year of birth, gender and doctor’s practice.

In all, 32.5% of epilepsy patients and 22.5% of controls had a diagnosis of a psychiatric disorder. In this group, epilepsy patients were a significant 2.5-fold more likely than controls to attempt suicide up to and including the date of the epilepsy diagnosis.

The same was true for study participants without a psychiatric diagnosis, with epilepsy patients having a 2.6-fold increased risk of a suicide attempt. The association remained after excluding participants who had received antiepileptic drugs (AEDs) prior to the epilepsy diagnosis date.

And patients with epilepsy who attempted suicide were at increased risk of a second attempt before their diagnosis date, at a 1.8-fold increased risk relative to controls after a first suicide attempt. Again, this effect persisted after excluding patients prescribed AEDs.

However, the researchers stress the potential for confounding in an observational study and say that they therefore “draw no inferences about the effects of AEDs.”

But they also note that AEDs carry a mandatory warning about suicidal thoughts. This prompted much research into the association, they say, but most studies “ignored the possibility that incident and recurrent suicide attempts may have preceded AED use.”

The team says: “Our study addresses this by considering the occurrence and recurrence of suicide attempts prior to the onset of epilepsy.”

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