Abstract: 98

Type: Oral

Abstract Category: Neuropsychology

Depression is among the most common comorbidities in multiple sclerosis (MS) with a significant impact on quality of life and employment status. In addition, depression in MS is associated with poorer cognitive performance. Previous studies have shown selective subregional hippocampal atrophy, alterations in diurnal cortisol secretion patterns and cognitive impairment in MS patients with depressive symptoms, similar to those reported in idiopathic major depressive disorder (iMDD). However, the relationship of comorbid major depressive disorder in MS (MS+MDD) to iMDD has not been established. We performed structured interviews, detailed cognitive testing and obtained high resolution structural MR imaging in four subject cohorts (MS+MDD, MSonly, iMDD and healthy controls (HC)) to contrast comorbid MDD in MS with idiopathic MDD.

Method: A total of 105 subjects were enrolled at a single center. They underwent the structured clinical interview for psychiatric disorders (SCID) and a detailed neuropsychological testing battery. All subjects also had a complete neurological exam that included determination of the EDSS and MS Functional Composite (MSFC). High resolution structural brain MR imaging was collected on a 3T scanner. Brain volumes were obtained using an automated algorithm (FIRST) with correction for head size. Analysis of cognitive testing results were performed with adjustment for age and sex (ANCOVA) using percentile test scores.

Results: Both right and left total hippocampal volumes were significantly reduced in both MS patient groups (p < 0.01) compared to healthy controls. Hippocampal volume loss was most pronounced in the right hippocampus of the comorbid MS+MDD group. All patient groups (MS+MDD, MSonly, iMDD) demonstrated impaired verbal learning as compared to the healthy controls (ANCOVA p=0.009) with idiopathic MDD the most impaired. Delayed verbal memory (0.06) and processing speed (0.07) showed trends for group differences in the patients versus HC.

Conclusions: MS related MDD is associated with significant cognitive impairment and hippocampal volume loss. These effects share features with, but are distinct from, idiopathic MDD suggesting that different pathophysiological underpinnings may exist between these forms of major depressive disorder.

Disclosure:

Stefan Gold: Receives funding from the National MS Society, the German Federal Ministry of Education and Research (BMBF), and the German Research Foundation (DFG)

Mary-Frances O´Connor: Receives funding from the DANA foundation

Enrique Lopez: No disclosures

Cristina Yamakawa: No disclosures

Kimberly Smith: No disclosure

Brian Renner: No disclosures

Yonggang Shi: Receives funding from the National MS Society

Jin Kyu Gahm: No disclosures

Nancy L. Sicotte: Receives funding from the National MS Society