Interictal psychiatric comorbidities of drug-resistant focal epilepsy: Prevalence and influence of the localization of the epilepsy.

Psychiatric comorbidities are 2 to 3 times more frequent in patients with epilepsy than in the general population. This study aimed to prospectively assess the following: (i) the prevalence of specific and nonspecific interictal psychiatric comorbidities in a population of patients with drug-resistant focal epilepsy and (ii) the influence of epilepsy lateralization and localization on these psychiatric comorbidities. In this prospective monocentric study, we collected demographic data, characteristics of the epilepsy, interictal psychiatric comorbidities, mood, anxiety, and alexithymia dimensions. We used criteria from Diagnostic and Statistical Manual of Mental Disorders IV ( DSM IV) (Mini International Mental Interview (MINI)), diagnosis criteria for specific comorbidities, and validated mood and anxiety scales (general and specific for epilepsy). Among the 87 enrolled patients (39 males, 48 females), 52.9% had at least one psychiatric comorbidity. The most common comorbidity was anxiety disorder (28.7% according to the MINI, and 38.4% screening by the Generalized Anxiety Disorder 7 (GAD 7)). Mood disorders were the second most frequent psychiatric comorbidity: 21.8% of our patients had interictal dysphoric disorders (IDDs), 16.1% presented major depressive disorders according to the MINI, and 17.2% screening by the Neurological Disorders Depression Inventory for Epilepsy (NDDIE). Patients with temporal lobe epilepsy had a higher prevalence of psychiatric comorbidities than patients with extratemporal lobe epilepsy (p = 0.002), which is probably related to a higher rate of anxiety disorders in this subgroup (p = 0.012). Prevalence of psychiatric disorders prior to epilepsy in patients was higher in right- than in left-sided epilepsy (p = 0.042). No difference was found according to limbic involvement at seizure onset. Overall, this article highlighted a very high proportion of anxiety disorders in these patients with drug-resistant focal epilepsy and the necessity to systematically detect them and thus lead to a specific treatment.