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Background: Anhedonia and abnormalities in reward behavior are core features of major depressive disorder (MDD). Convergent evidence indicates that overweight/obesity (OW), a highly prevalent condition in MDD, is independently associated with reward disturbances. We therefore aimed to investigate the moderating effect of OW on the willingness to expend efforts for reward in individuals with MDD and healthy controls (HC)., Methods: Forty-one adults (HC n = 20, MDD n = 21) completed the Effort Expenditure for Rewards Task (EEfRT), clinical and cognitive measures. Anthropometric parameters were assessed in all participants, and an additional evaluation of laboratorial parameters were conducted solely on those with MDD. Individuals with MDD were all on vortioxetine monotherapy (10-20 mg/day)., Results: Interactions between reward magnitude, group and OW were observed (χ 2  = 9.192, p = 0.010); the OW-MDD group chose the hard task significantly less than normal weight (NW)-HC (p = 0.033) and OW-HC (p = 0.034), whereas there were no differences between NW-MDD and HCs. Within individuals with MDD, the proportion of hard task choices was more strongly correlated with body mass index (BMI) (r = -0.456, p = 0.043) and insulin resistance (HOMA2-IR) (r = -0.467, p = 0.038), than with depressive symptoms (r = 0.290, p = 0.214)., Conclusions: OW significantly moderated the association between MDD and willingness to make efforts for rewards. These findings offer novel evidence on the potential role of metabolic factors on the basis of anhedonia, and for the heuristic models proposing a pathophysiological connection between mood and metabolic disorders., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Anhedonia is defined as a diminished ability to experience interest or pleasure, and is a critical psychopathological dimension of major depressive disorder (MDD). The purpose of the current systematic review is to evaluate the therapeutic efficacy of pharmacological treatments on measures of anhedonia in adults with MDD. Electronic databases Cochrane Library (CENTRAL), Ovid MEDLINE, PubMed, PsycINFO, and Google Scholar were searched from inception to June 1, 2018 for longitudinal studies utilizing pharmacotherapy for the treatment of anhedonia in patients with MDD. A total of 17 eligible studies were identified (i.e., evaluated the effects of pharmacotherapy on a measure of anhedonia). Among the identified studies, the efficacy of 14 different pharmacotherapies on measures of anhedonia were evaluated, including melatonergic agents (i.e. agomelatine), monoaminergic agents (i.e. moclobemide, clomipramine, bupropion, venlafaxine, fluoxetine, amitifadine and levomilnacipran, escitalopram, and sertraline), glutamatergic agents (i.e., ketamine and riluzole), stimulants (i.e., methylphenidate), and psychedelics (i.e., psilocybin). Based on the available evidence, most antidepressants demonstrated beneficial effects on measures of anhedonia as well as the other depressive symptoms. Only escitalopram/riluzole combination treatment was ineffective in treating symptoms of anhedonia in MDD. Continued research is warranted to further support the efficacy of mechanistically-distinct antidepressants in treating symptoms of anhedonia in MDD. Future research should also aim to parse out the heterogeneous effects of different pharmacotherapies on anhedonic symptoms., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Background: Anhedonia is a common, persistent, and disabling phenomenon in treated adults with Major Depressive Disorder (MDD). Hitherto, relatively few antidepressant agents have been evaluated with respect to their effect on anhedonia in MDD. Methods: This is a post-hoc analysis of a primary study that sought to evaluate the sensitivity to change of the THINC-integrated tool (THINC-it) in MDD (ClinicalTrials.gov Identifier: NCT03053362). Adults meeting DSM-5 criteria for MDD with at least moderate depressive symptom severity [i.e., Montgomery Åsberg Depression Rating Scale (MADRS) total score ≥20] were eligible. Subjects were recruited between October 2017 and August 2018 in Toronto, Ontario at the Brain and Cognition Discovery Foundation. All subjects received open-label vortioxetine (10–20 mg/day, flexibly-dosed) for 8 weeks. Herein, the primary outcome of interest was the change from baseline to endpoint in the Snaith-Hamilton Pleasure Scale (SHAPS) total score, as well as the MADRS anhedonia factor. The mediational effects of improvements in anhedonia on general function and quality of life, as measured by the Sheehan Disability Scale (SDS) and the 5-Item World Health Organization Well-Being Index (WHO-5), were secondarily assessed. Results: A total of 100 subjects with MDD were enrolled in the primary study and began treatment with vortioxetine. Vortioxetine significantly improved anhedonia as evidenced by significant baseline to endpoint improvements in SHAPS and MADRS anhedonia factor scores (p < 0.0001). Improvements in the SHAPS and the MADRS anhedonia factor correlated with improvements in general function (i.e., SDS) and quality of life (i.e., WHO-5) (p < 0.0001). Notably, improvements in anhedonia were found to mediate the association between improvements in overall depressive symptom severity (i.e., MADRS total score) and social functioning (i.e., social life component of the SDS) (p = 0.026). Conclusion: The unmet need in depression is to improve patient functioning and other patient-reported outcomes (e.g., quality of life). Antidepressant interventions capable of attenuating anhedonia as well as cognitive dysfunction in MDD may help in this regard, as improvement in these domains have been associated with improvement in psychosocial function and quality of life. [ABSTRACT FROM AUTHOR]

It is well established that deficits in motivation, reward, and cognition are common during and in between syndromal episodes of depression as part of Major Depressive Disorder (MDD). Informed by evidence indicating functional and structural interconnectivity between cognitive and reward brain circuits, we preliminarily evaluate the association between measures of cognitive performance and reward/motivation. This is a post-hoc analysis of a primary study (i.e. the THINC-it sensitivity to change study). Adults (18–65 years of age) meeting DSM-5 criteria for MDD, single-episode or recurrent confirmed by M.I.N.I. with moderate severity or greater (i.e. Montgomery Asberg Depression Rating Scale ≥20). All eligible subjects received vortioxetine 10–20 mg open-label for 8 weeks. The Effort Expenditure Reward Task (EEfRT) was the principal measure of motivation and reward. We directly compare the effects of cognitive measures and depressive symptoms on effort-based decision-making using the THINC-it composite score and MADRS total score. Twenty-one participants with MDD (Mean age = 38.47, SD = 12.85) and 20 healthy volunteers (Mean age = 41.50, SD = 14.21) completed the optional EEfRT task. Amongst individuals with MDD, performance in processing speed, executive function (i.e. Trails B) and overall composite cognitive score was positively associated with the proportion of hard-task choices in the high reward condition (i.e. greater reward valuation). Across both groups, a greater probability (χ2 = 1.137) and magnitude of reward (χ2 = 0.045) was associated with increased effort (i.e. choosing the hard task more frequently). Using fully factored GEE models, we observed a positive association between performance on the Trails test (β = 2.223, SE = 0.928, p = 0.017) as well as the composite score (β = 0.978, SE = 0.0.459, p = 0.033), and greater effort for high rewards. In addition, it was observed that a positive association (i.e. greater effort for reward in higher probability) was observed with depressive symptoms and overall cognitive measures. Herein, we observed that an association exists between overall cognitive function, notably processing speed and executive function and reward function. Specifically, a greater effort for hard task rewards (using the EEfRT task) was manifested in individuals exhibiting higher levels of cognitive performance in a well-characterized sample of MDD treated with Vortioxetine. • Cognitive function highly correlates with measures of reward and motivation in adults with major depressive disorder (MDD) • Processing speed, executive function and overall cognition was positively associated with greater reward valuation • Overall cognition positively correlated (i.e. greater effort for reward in higher probability) with depressive symptoms • Self-reported measures of anhedonia and reward valuation are distinct domains of psychopathology in those with MDD [ABSTRACT FROM AUTHOR]