Psychiatric disorders in patients with psychogenic nonepileptic seizures and drug-resistant epilepsy: a study of an Argentine population.

Epidemiological data show that up to 20-30% of patients with psychogenic nonepileptic seizures (PNESs), resembling drug-resistant epilepsy (DRE), are referred to tertiary epilepsy centers. Furthermore, both disorders present high psychiatric comorbidity, and video-EEG is the gold standard to make differential diagnoses. In this study, we described and compared the clinical presentation and the frequency of psychiatric disorders codified in DSM IV in two groups of patients, one with PNESs and the other with DRE, admitted in a tertiary care epilepsy center of Buenos Aires, Argentina. We included 35 patients with PNESs and 49 with DRE; all were admitted in the video-EEG unit in order to confirm an epilepsy diagnosis and determine surgical treatment possibilities. All patients underwent a neurological and psychiatric assessment, according to standardized protocol (SCID I and II; DSM IV criteria). Student's t test was performed to compare continuous variables and Chi square test to compare qualitative variables. In this study, 33 (67%) patients with DRE and 35 (100%) patients with PNESs met criteria for at least one disorder codified in Axis I of DSM IV (p=0.003). Differences in the frequency of psychiatric disorder presentation were found between groups. Anxiety disorders (16.32% vs 40%; p=0.015), trauma history (24.5% vs 48.57%; p=0.02), posttraumatic stress disorder (4.08% vs 22.85%; p=0.009), and personality cluster B disorders (18.37% vs 42.86%; p=0.02) were more frequent in the group with PNESs. Psychotic disorders were more frequent in the group with DRE (20.4% vs 2.85%; p=0.019). Depression was equally prevalent in both groups. Standardized psychiatric assessment provides information that could be used by the mental health professional who receives the referral in order to improve quality of care and smooth transitions to proper PNES treatment, which should include a multidisciplinary approach including neurology and psychiatry.