Abstracts

Rationale: Mood and anxiety disorders are the most common psychiatric co-morbidities in epilepsy. Mesial temporal structural changes have been documented in patients with primary mood disorders and are a common finding in temporal lobe epilepsy (TLE). The purpose of this study is to establish if patients with treatment-resistant focal epilepsy (TRFE) and comorbid mood and / or anxiety disorders are more likely to have differences in hippocampal and amygdala volumes compared to those without psychiatric comorbidities. Methods: Manual and automatic quantitative volumetric measurements of hippocampus and amygdala were performed in 3T high-resolution brain MRI studies of 53 patients [Females: n=28(53%); Right-handed, n=41(79%). Psychiatric diagnoses included Depression only, anxiety disorder only, depression + anxiety disorders, suicidal risk) were established with the MINI International Neuropsychiatric Interview. Since depressive disorders may also display symptoms of anxiety, patients completed the self-rating scale Generalized Anxiety Disorder- 7 (GAD-7). Independent samples T-test was used to identify significant differences in volumes between symptomatic and asymptomatic patients. A separate analysis was also carried out among patients without mesial temporal sclerosis. Results: Patients’ mean age and duration of the seizure disorder were 38±13 and 18±13 years, respectively.  TLE was diagnosed in 30 patients (MTS, n=14) and Extra-Temporal epilepsy in 23 (MTS=3). According to the MINI, 21 patients (39%) were in the symptomatic group: 8 patients (15%) met criteria for both anxiety and depressive disorder and 13 patients had (24.5%) either and an anxiety or a depressive disorder. Having TLE with and without MTS was not associated with a higher prevalence of depression and anxiety disorders.  There was no significant difference in the volume of mesial temporal structures between symptomatic and asymptomatic patients. When volumes were compared according to the psychiatric diagnosis, there was a statistical trend (p = 0.06) suggesting a smaller left amygdala among patients with depression When patients with MTS were excluded from the analysis, a smaller left amygdala was identified (p= 0.02). Furthermore, patients with depression on the MINI + symptoms of anxiety on the GAD-7 were found to have a significantly larger left hippocampus (p=0.01). In addition, patients with an increased suicidality risk had smaller hippocampi (p=0.05) and amygdalae (p=0.04) bilaterally. Conclusions: Mood and anxiety disorders appear to have an impact in the volume of mesial temporal structures in patients with TRFE, with a worse effect identified among patients with a suicidality risk. Funding: Self-funded study