Abstracts

Rationale: Depression is the most common psychiatric co-morbidity in patients with epilepsy (PWE) with a lifetime prevalence of approximately 30 %. Concern for the pro-convulsive properties of certain antidepressants has led to under-treating depression and anxiety disorders in these patients. Data from animal models and open trials of selective serotonin re-uptake inhibitors (SSRI's) in patients with treatment resistance epilepsy have suggested a potential anticonvulsant effect of these medications. The primary aim of this study was to establish if SSRIs and serotonin-norepinephrine reuptake inhibitors (SNRIs) were associated with an improvement in seizure frequency in PWE. The secondary aim was to determine whether there was a correlation between improvement in psychiatric symptoms and seizure frequency. Methods: This was a retrospective observational study of 100 consecutive PWE started on SSRIs or SNRIs for the treatment of depressive and/or anxiety disorders. Seizure frequency was recorded from medical records six months prior to introduction of antidepressants and three and six months after initiating therapy. 16 patients were excluded from the analysis due to changes in antiepileptic drug regimen/doses (n = 10), or procedures (n =6) at the time of introduction of the antidepressant. Final analysis using dichotomized outcome of seizure frequency (<1/month and ≥ 1/month) was conducted in 84 patients. Responder rate was calculated in patients with a seizure frequency ≥ 1/month. Changes in mood and anxiety data was obtained from the clinical assessment by AMK at three and six months after treatment and were divided into two categories: unchanged and improvement/remission. 13 patients were excluded due to insufficient data. Results: Among the 84 patients, 40 patients had a seizure frequency ≥ 1/month. Eleven of these patients (27.5%) had a reduction in seizure frequency and 28 (70 %) remained unchanged. Two patients had an increment in their seizure frequency from 1/month to 2-3/month. 44 patients had a seizure frequency <1/month which remained unchanged in all. None of the patients discontinued antidepressants before six months. Responder rate was 40 % (16/40). Six month after the start of therapy, improvement and/or remission of psychiatric symptoms occurred in 61/71 patients (86%). The relation between changes in psychiatric symptoms and seizure frequency appear in Table 1. Conclusions: SSRIs and SNRIs do not appear to worsen seizure frequency in PWE. In patients with frequent seizures SSRIs and SNRIs appear to have an antiepileptic effect. These drugs appear to yield good therapeutic response independently of seizure frequency.These data need to be replicated in prospective double blind placebo controlled trials.