Good seizure control needed to tackle depression after epilepsy surgery
MedWire News: Improved depressive symptoms are more likely to be maintained if patients have good seizure control after epilepsy surgery, say researchers.
Hamada Hamid (Yale University School of Medicine, New Haven, Connecticut, USA) and team investigated the possibility that seizures may cause the mood changes experienced by approximately 20-50% of people with epilepsy.
The study, published in the journal Neurology, involved 373 patients (mean age 37.7 years) who underwent at least one evaluation of their depression symptoms using the Beck Depression Inventory (BDI). This initial pre-surgery assessment identified 22.7% of patients as moderately to severely depressed and 64.1% as not depressed.
Not all these patients were available for re-evaluation 5 years later; 256 completed the study. However, there was no significant difference in baseline BDI scores between the completers and noncompleters. After 5 years, 14.8% of the patients were moderately to severely depressed and 77.3% were not depressed.
Epilepsy control was rated "excellent" in patients who experienced no seizures in the 5 years following surgery, "good" in those who had no seizures for 2 consecutive years, "fair" if this was for 1 year, and "poor" if they did not have a year free from seizures.
The researchers found that the 105 patients who had good seizure control experienced significantly greater reductions in BDI scores than those with poor seizure control. The mean change in BDI score from baseline to 5-year follow-up was -4.33 for the patients rated as "excellent" and -3.63 for the "good" group. The equivalent changes in the "fair" and "poor" rated patients were not significant (0.04 and 0.16, respectively).
They also found that patients with depressive disorders (diagnosed according to the World Mental Health Composite International Diagnostic Interview, prior to surgery) had the greatest reductions in BDI at follow up.
However, the authors acknowledge the limitations of their study: "Our data cannot determine whether depressive symptoms are a part of peri-ictal phenomenon or a psychological response to experiencing breakthrough seizures."
The study also failed to systematically record use of antidepressant medication, cognitive behavior therapy, or other therapies among the participants, they note.
"Because psychotherapeutic and psychotropic management were not adequately monitored in this study, we may not draw conclusions on whether epilepsy surgery directly improves mood symptoms," say Hamid and colleagues. "However, subjects who achieved good seizure control after surgery also experienced long-term mood improvement."
They emphasize the need for further research "to explore the long-term temporal relationship between seizures and mood symptoms," suggesting that "measurement of access to and quality of mental health care should be incorporated into epilepsy surgical outcomes studies."
By Chloe McIvor