Investigating reward motivation and sensitivity in healthy volunteers with high vs low state anhedonia

The aim of this study is to examine whether there are differences in motivation for reward (using the Joystick Operated Runway Task and Effort Expenditure for Reward Task) and sensitivity to reward (using the Sweet Taste Test) in healthy controls who have high vs low state anhedoni

A novel biomarker of interleukin 6 activity and clinical and cognitive outcomes in depression

Background:Inflammatory cytokines like interleukin-6 (IL-6) are implicated in depression, but most studies have hitherto focused on circulating levels of IL-6 rather than its activity. IL-6 trans-signalling is thought to be responsible for most of the pathogenic effects of IL-6 and is implicated in autoimmune diseases like rheumatoid arthritis. We tested the association between a multi-protein-derived measure of IL-6 trans-signalling and clinical and cognitive outcomes in patients with depression. We hypothesised that this novel measure of IL-6 activity/bioavailability would be associated with clinical and cognitive measures previously reported to be associated with inflammation in depression.Methods:Using data from 86 patients with International Classification of Diseases-10 diagnosis of depression, we calculated a ratio score representing IL-6 activity/bioavailability using serum IL-6, soluble IL-6 receptor (sIL-6R), and soluble glycoprotein 130 levels. We tested the relationship of this novel biomarker with 12 cytokines using correlation analyses and with cognitive and clinical measures using multivariable linear regression, following z-transformation of all immune exposures.Results:The novel measure of IL-6 activity/bioavailability was correlated with IL-6 (r=0.42, P=0.03), C-reactive protein (CRP) (r=0.42, P=0.03), sIL-6R (r=0.91, P&lt;0.01), and tumour necrosis factor alpha (r=0.43, P=0.03). The IL-6 activity/bioavailability measure was associated with higher somatic symptoms of depression (β=1.09; 95% CI 0.30, 1.88; PFDR=0.01), fatigue (β=4.34; 95% CI 1.26, 7.42; PFDR=0.03), depression severity (β=3.06; 95% CI 0.71, 5.40; P=0.02), poorer quality of life (β=−0.07; 95% CI −0.13, −0.01; PFDR=0.045), and decreased psychomotor speed (β=−5.46; 95% CI −9.09, −1.84; PFDR=0.01),. There was little evidence of associations with reaction time, anhedonia, anxiety, emotional perception and recall, executive function, and sustained attention (Ps&gt;0.05). The effect estimates for the associations of the novel measure with depression outcomes were comparable to those for individual immune proteins (i.e., IL-6, CRP, sIL-6R).Conclusion:A novel multi-protein-derived measure of IL-6 activity/bioavailability shows robust associations with various inflammation-related clinical and cognitive outcomes in depression and performs well in comparison to single inflammatory proteins. We need replication of these findings in other samples, experiments for mechanistic validity of this novel biomarker, and clinical studies to assess its usefulness as a marker of illness risk and prognosis.</div

Objective measures of reward sensitivity and motivation in people with high vs low anhedonia

This study was an experimental human study which examined different components of reward processing in people who scored high or low on an anhedonia questionnaire in a non-clinical population. The deposit includes the anonymised open access data, the information sheet and consent form