This is a systematic review from 2013.  It found that Epilepsy was significantly associated with depression and depression was observed to be highly prevalent in people with epilepsy (PWE).
23 articles reported on 14 unique data sources. Nine studies reported on 29,891 PWE who had an overall prevalence of active (current or past-year) depression of 23.1% (95% confidence interval [CI] 20.6%–28.31%). Five of the 14 studies reported on 1,217,024 participants with an overall OR of active depression of 2.77 (95% CI 2.09–3.67) in PWE. For lifetime depression, 4 studies reported on 5,454 PWE, with an overall prevalence of 13.0% (95% CI 5.1–33.1), and 3 studies reported on 4,195 participants with an overall OR of 2.20 (95% CI 1.07–4.51) for PWE.
1 Fiest KM, Dykeman J, Patten SB, et al. Depression in epilepsy: A systematic review and meta-analysis. Neurology 2013;80:590–9. doi:10.1212/WNL.0b013e31827b1ae0