Selective serotonin reuptake inhibitor and serotonin-norepinephrine reuptake inhibitor antidepressants did not increase seizure frequency in a retrospective series of epilepsy patients seen at Rush University Medical Center in Chicago.

The researchers investigated how 84 adult epilepsy patients fared after being put on the drugs for 6 months. None had an increase – and some actually had a decrease – in seizure frequency, and almost all had improvements in their baseline depression and anxiety.

Dr. Ramses Ribot

“There’s a long-held misconception that antidepressants have proconvulsive properties,” probably because a few older tricyclic antidepressants and bupropion do, said lead investigator Dr. Ramses Ribot, a neurophysiology fellow at Rush.

That concern has carried over to SSRIs and SNRIs, for which there is no evidence of a proseizure effect. As a result, neurologists “are very hesitant to” prescribe the newer agents to epilepsy patients, and depression and anxiety – both common in epilepsy – remain “definitely undertreated,” Dr. Ribot said at the annual meeting of the American Epilepsy Society.

Seventy-nine patients in the study were on SSRIs, most commonly escitalopram (Lexapro); the remaining five were taking SNRIs.

Among the 44 who entered the study with fewer than one seizure per month, seizure frequency did not change during antidepressant therapy.

Among the 40 patients who entered with 1-12 seizures per month, seizure frequency was reduced to fewer than one per month in 11 (27.5%) and did not change in 27 (68%). Seizures increased from one per month to two or three in two patients. Overall, 16 (40%) of the 40 patients had a greater than 50% reduction in seizure frequency.

The findings suggest that “these medications could have an anticonvulsant effect” – something that’s been suggested in previous research as well, Dr. Ribot said (Neurology 1995;45:1926-7).

Sixty-one of the 71 patients (86%) for whom psychiatric evaluations were available had improvements or remissions of depression and anxiety symptoms while on antidepressants, a finding that appeared to be independent of seizure frequency.

There were no procedural interventions or changes to antiepileptic drug regimens during the study and the 3 months leading up to it. The patients were over 18 years old, about evenly split between men and women, and clinically diagnosed with depression or anxiety disorders at baseline.

The researchers said that they have no disclosures.