Abstract Details

Title Reduced Reward Responsiveness: A Unique Phenotypic Presentation of Depressive Symptoms in Multiple Sclerosis

Topic Multiple Sclerosis

Presentation(s) P10 - Poster Session 10 (8:00 AM-9:00 AM)

Poster/Presentation
Number 12-002

Background Research on depression has progressed toward elucidating various phenotypic presentations with discrete biological bases (e.g., anhedonia, irritability). For instance, inflammation leads to reduced reward responsiveness due to downregulation of dopamine in the ventral striatum. Depression is prevalent in MS, but disease-specific features of MS depression are unknown. As an autoimmune disease, we predicted lower reward responsiveness in MS versus non-MS depression.

Objective To investigate reward responsiveness in people with multiple sclerosis (MS) depression as compared to non-MS depression.

Design/Methods MS patients (n=169) and healthy controls (n=186) aged 25-65 completed the Mental Health Inventory to measure depression (MHI-D) and the Behavioral Inhibition System / Behavioral Activation System scales to characterize drive (e.g., “I go out of my way to get things I want”), reward responsiveness (e.g., “It would excite me to win a contest”), and behavioral inhibition (e.g., “I worry about making mistakes”). Scores were adjusted for age and sex. Independent two-tailed t-tests examined differences between patients and controls within (a) the whole sample and (b) a subset with at least mild depression (MHI-D >75%ile) to examine phenotypic differences between depression characteristics in MS patients versus controls.

Results Overall, patients had worse depression (p=0.005, Cohen’s d=0.30), behavioral inhibition (p=0.014, d=0.26), and reward responsiveness (p=0.044, d=0.22) than controls, without differences in reported drive (p=0.511, d=0.07). Among subjects with at least mild depression, patients (n=78) had lower reward responsiveness than controls (n=48; p=0.034, d=0.38) despite similar MHI-D scores (p=0.547, d=0.11); there were no reliable differences in drive (p=0.468, d=0.13) or behavioral inhibition (p=0.093, d=0.31).

Conclusions Individuals with MS depression exhibit reduced reward responsiveness when compared to non-MS depression. These results suggest that MS depression presents with a distinct clinical phenotype marked by a lack of sensitivity to signals of reward. Further elucidating these differences will inform how to best treat MS-specific depression.

Authors/Disclosures
Tali R. Sorets PRESENTER	Tali R. Sorets has nothing to disclose.
	No disclosure on file
James F. Sumowski (Icahn School of Medicine At Mount Sinai)	Mr. Sumowski has nothing to disclose.