Epilepsy and Depression: Commonly Comorbid, Often Undertreated

Author: Jeannette Y. Wick, RPh, MBA, FASCP

A number of recent studies have investigated the relationship between epilepsy and depression, providing insights into both conditions. 

Experts acknowledge that epilepsy and depression occur often as comorbidities, but it is unclear how the 2 conditions are related. The chronic stresses and limitations of epilepsy may cause depression. Or, the conditions may be related genetically, as animal models appear to indicate. At the American Academy of Neurology's April 2012 annual meeting in San Diego, 2 poster presentations underscored the difficulties of diagnosing and treating comorbid depression and epilepsy.
 
The first study from the poster presentation, carried out by researchers at the University of Calgary, looked at population-based studies that assessed the association between depression and epilepsy. The researchers used data from 11 studies, which were based on 7 unique samples including 11,716 participants with epilepsy and 1,397,354 participants without epilepsy. They determined that the pooled odds ratio of depression for participants with epilepsy was 2.43, higher than the odds ratio for depression associated with having a chronic illness. This seems to support the hypothesis that epilepsy and depression share a common genetic cause.
 
Untreated depression may also increase the likelihood of diminished epilepsy control. The second study from the poster presentation, carried out by researchers at Rush University Medical Center in Chicago, set out to determine whether selective serotonin reuptake inhibitors (SSRIs) and serotonin–norepinephrine reuptake inhibitors (SNRIs) could improve seizure control in patients with poorly controlled epilepsy. This retrospective observational study found that seizure frequency improved in approximately a fourth of patients treated for depression with SSRIs or SNRIs. Equally as important, the results indicated that these drugs are safe treatment options for patients with epilepsy.
 
Some prescribers hesitate to prescribe antidepressants for people with epilepsy, however, based on fears of drug interactions. A study published in the June 2012 edition of Epilepsia is of particular interest to pharmacists. In it, the researchers find that patients who have depressive and anxiety disorders report more severe adverse reactions to antiepileptic drugs, even if their depression or anxiety is mild to moderate.
 
Clearly, clinicians need to screen patients who have epilepsy for comorbid mental illnesses, and treat them appropriately.

Ms. Wick is a visiting professor at the University of Connecticut School of Pharmacy and a freelance writer from Virginia.