The impact of overweight/obesity on monetary reward processing: A systematic review

Impact of Elevated Body Mass Index (BMI) on Hedonic Tone in Persons with Post-COVID-19 Condition: A Secondary Analysis

INTRODUCTION

The post-COVID-19 condition (PCC) is characterized by persistent, distressing symptoms following an acute COVID-19 infection. These symptoms encompass various domains, including hedonic tone, which is critical for overall well-being. Furthermore, obesity is both a risk factor for COVID-19 and PCC and associated with impaired hedonic tone. This study aims to investigate whether elevated body mass index (BMI) is associated with hedonic tone in persons with PCC.

METHODS

We perform a post hoc analysis of a randomized, double-blind, placebo-controlled clinical trial investigating the impact of vortioxetine on cognitive impairment in persons with PCC. Statistical analysis of baseline data using a generalized linear model was undertaken to determine the relationship of BMI to hedonic tone measured by Snaith-Hamilton Pleasure Scale (SHAPS) scores. The model was adjusted for covariates including age, sex, race, suspected versus confirmed COVID-19 cases, alcohol amount consumed per week, and annual household income.

RESULTS

The baseline data of 147 participants were available for analysis. BMI had a statistically significant positive association with baseline SHAPS total scores (β = 0.003, 95% CI [6.251E-5, 0.006], p = 0.045), indicating elevated BMI is associated with deficits in self-reported reward system functioning.

CONCLUSION

Higher BMI is associated with greater deficits in hedonic tone in persons with PCC, which may impact reward functioning processes such as reward prediction and processing. The mediatory effect of BMI on reward function underscores the need to investigate the neurobiologic interactions to elucidate preventative and therapeutic interventions for persons with PCC. Therapeutic development targeting debilitating features of PCC (e.g., motivation, cognitive dysfunction) could consider stratification on the basis of baseline BMI.

TRIAL REGISTRATION NUMBER

NCT05047952.

Brain structural and functional alterations in individuals with combined overweight/obesity and mood disorders: A systematic review of neuroimaging studies

Growing evidence suggests there is a bidirectional relationship between depression and obesity, which are associated with structural and functional brain abnormalities. However, the underlying neurobiological mechanisms subserving the foregoing associations have yet to be characterized. It is necessary to summarize the neuroplastic brain changes in relation to depression and obesity. We systematically searched articles from 1990 to November 2022 on databases including MEDLINE/PubMed, Web of Science, PsycINFO. Only neuroimaging studies within the scope of potential differences in brain function and structure in individuals with depression and obesity/ BMI changes were included. Twenty-four eligible studies were included in the review herein, consisting of 17 studies reporting changes in brain structure, 4 studies reporting abnormal brain function, and 3 studies reporting both changes in brain structure and function. Results indicated an interaction between depression and obesity on brain functions, and their influence on brain structure is both extensive and specific. Overall, reduced whole brain, intracranial, and gray matter volume (e.g. frontal, temporal gyri, thalamic, and hippocampal) and impaired white matter integrity was observed in persons with depression and obesity comorbidity. Additional evidence on resting state fMRI reveals select brain regions associated with cognitive control, emotion regulation, and reward functions. Due to the diversity of tasks in task fMRI, the distinct neural activation patterns are revealed separately. The bidirectional relationship between depression and obesity reflects different characteristics in brain structure and function. Longitudinal designs should be reinforced in follow-up studies.

Aberrant reward-related neural activation: Dimensional correlate of binge-eating severity or categorical marker of binge eating?

Binge eating (BE) is characterized by consuming an objectively large amount of food in a short period of time and experiencing loss of control over one's eating. The neural underpinnings of monetary reward anticipation and their association with BE severity remain poorly understood. Fifty-nine women aged 18 to 35 (M = 25.67, SD = 5.11) with a range of average weekly BE frequency (M = 1.96, SD = 1.89, range = 0-7) completed the Monetary Incentive Delay Task during fMRI scanning. Mean percent signal change within the left and right nucleus accumbens (NAc) during anticipation of monetary gain (versus non-gain) was extracted from a priori-defined functional 5 mm spheres and correlated with average weekly BE frequency. Exploratory voxel-wise whole-brain analyses examined the association between neural activation during anticipation of monetary reward and average weekly BE frequency. Body mass index and depression severity were covariates of non-interest in analyses. Mean percent signal change in the left and right NAc inversely correlated with average weekly BE frequency. Whole-brain analysis revealed no significant associations between neural activation during reward anticipation and average weekly BE frequency. In exploratory case-control analyses, mean percent signal change in the right NAc was significantly lower in women with BE (n = 41) versus women without BE (n = 18), but whole-brain analyses revealed no significant group differences in neural activation during reward anticipation. Decreased right NAc activity during monetary reward anticipation may distinguish women with and without BE.

Evaluating the neural substrates of effort-expenditure for reward in adults with major depressive disorder and obesity

Converging evidence has suggested that disturbances in monetary reward processing may subserve the shared biosignature between major depressive disorder (MDD) and obesity. However, there remains a paucity of studies that have evaluated the deficits in specific subcomponents of reward functioning in populations with MDD and obesity comorbidity. We evaluated the association between effort-expenditure for monetary reward and neural activation in regions associated with reward-based decision making (i.e., the caudate nucleus, anterior cingulate cortex (ACC) and hippocampus) in people with MDD and obesity comorbidity. We acquired structural and functional magnetic resonance imaging (fMRI) in 12 participants and performed a spherical region-of-interest analysis (ROI) using previously defined peak MNI coordinates. A one-sample t-test was employed to compare ROI-specific blood-oxygen-level-dependent (BOLD) signal change during the task choice selection window (i.e., high-effort vs. low-effort task) of the effort-expenditure for reward task (EEfRT). We observed no change in activation of the caudate nucleus, ACC or hippocampus in participants with increased BMI when contrasting the high effort > low effort reward magnitude condition for the EEfRT. The findings from our exploratory study evaluated the disturbances in fundamental reward processes, including cost-benefit decision making, in people MDD and obesity. Future studies should further investigate this relationship with a larger sample size.

Testing reward processing models of obesity using in-the-moment assessments of subjective enjoyment of food and non-food activities

OBJECTIVE

Although altered reward processing is proposed to play a key role in obesity maintenance, the role of food enjoyment and enjoyment of non-food naturally rewarding activities ("non-food enjoyment") in obesity maintenance remains unknown. This study examined how food and non-food enjoyment were associated with baseline body mass index (BMI) and weight loss (WL) following year-long behavioral WL treatment.

METHODS

At baseline, participants (MAge = 51.81; 73.8 % White, N = 279) with overweight/obesity completed a 7-day ecological momentary assessment (EMA) protocol inquiring about pleasure/enjoyment derived from eating and non-food activities over the past few hours. Participants also completed retrospective self-report measures of food/non-food enjoyment. With linear regressions, associations between EMA food/non-food enjoyment and BMI and post-treatment WL were examined. Race was included as a covariate.

RESULTS

EMA and retrospective food/non-food enjoyment measures had modest concordance, providing preliminary psychometric support for the EMA measures. Partially consistent with hypotheses, greater EMA food enjoyment was associated with lower BMI (B = -1.03, p = .01) and with greater WL, though the latter association was not statistically significant (B = 1.15, p = .07). Exploratory analyses suggested that race was associated with food enjoyment (non-White participants had greater food enjoyment than White participants, d = 0.81, p = .005), and that race may have affected associations between food enjoyment and weight outcomes. Associations between non-food enjoyment and weight outcomes were small and nonsignificant (ps > .93).

CONCLUSIONS

Results suggest enjoyment from food, but not from non-food domains, is associated with weight outcomes.

Risk Factors for Heart Disease in Working Railwaymen

Heart diseases are the most common non-communicable diseases worldwide. We examined the prevalence of risk factors for heart disease among a sub-population of working men. In total, 11,059 railway crew workers of the Russian Railways Company were included in the study. We also asked participants to answer several questions based on the WHO STEPwise approach to surveillance (STEPS) translated into Russian. Only 30% of drivers had normal body mass index (BMI), whereas 70% were overweight or obese. In 12% of subjects, total cholesterol was higher than 5 mmol/L. In 15% of participants, glucose level was higher than 5.5 mmol/L. 38% of drivers reported smoking. Physical inactivity was registered in 54% of persons. Only 29% ate according to the key principles of good diet quality. 24% of respondents had a family history of heart disease. MANOVA demonstrated that BMI was determined by age, profession, smoking, physical inactivity, and diet quality. As age increased, the number of people with normal cholesterol levels decreased. It was demonstrated that a correlation existed between glucose levels and BMI. In the total group, the correlation was 0.46 (p < .05). The correlation between those parameters increased due to age, from 0.33 in the <30 years of age group up to 0.52 in the >50 years of age group. This study demonstrated that there is a high prevalence of risk factors for heart disease in train drivers in the Russian Federation.

The clinical characterization of the adult patient with bipolar disorder aimed at personalization of management

Bipolar disorder is heterogeneous in phenomenology, illness trajectory, and response to treatment. Despite evidence for the efficacy of multimodal-ity interventions, the majority of persons affected by this disorder do not achieve and sustain full syndromal recovery. It is eagerly anticipated that combining datasets across various information sources (e.g., hierarchical "multi-omic" measures, electronic health records), analyzed using advanced computational methods (e.g., machine learning), will inform future diagnosis and treatment selection. In the interim, identifying clinically meaningful subgroups of persons with the disorder having differential response to specific treatments at point-of-care is an empirical priority. This paper endeavours to synthesize salient domains in the clinical characterization of the adult patient with bipolar disorder, with the overarching aim to improve health outcomes by informing patient management and treatment considerations. Extant data indicate that characterizing select domains in bipolar disorder provides actionable information and guides shared decision making. For example, it is robustly established that the presence of mixed features - especially during depressive episodes - and of physical and psychiatric comorbidities informs illness trajectory, response to treatment, and suicide risk. In addition, early environmental exposures (e.g., sexual and physical abuse, emotional neglect) are highly associated with more complicated illness presentations, inviting the need for developmentally-oriented and integrated treatment approaches. There have been significant advances in validating subtypes of bipolar disorder (e.g., bipolar I vs. II disorder), particularly in regard to pharmacological interventions. As with other severe mental disorders, social functioning, interpersonal/family relationships and internalized stigma are domains highly relevant to relapse risk, health outcomes, and quality of life. The elevated standardized mortality ratio for completed suicide and suicidal behaviour in bipolar disorder invites the need for characterization of this domain in all patients. The framework of this paper is to describe all the above salient domains, providing a synthesis of extant literature and recommendations for decision support tools and clinical metrics that can be implemented at point-of-care.

Interventions targeting comorbid depression and overweight/obesity: A systematic review

BACKGROUND

Overweight/obesity and depression are highly co-occurring conditions with shared pathophysiology as well as social and economic determinants. To our knowledge, this is the first systematic review aims to comprehensively synthesize extant literature with a focus on the effectiveness of interventions targeting obesity and depression comorbidity.

METHODS

We searched databases including MEDLINE, ProQuest Central, Web of Science, PsycINFO, Cochrane Library, from inception of the databases until Nov 12, 2021. Articles were included if they reported on the effects of pharmacological, psychological or dietary interventions on comorbid depression and overweight/obesity as their primary or secondary outcome.

RESULTS

Of the 5480 identified records, 19 eligible researches comprising 15 RCTs and 4 uncontrolled longitudinal studies for 3408 participants with comorbid depression and overweight/obesity. The available literature is not sufficient to inform evidence-based treatments targeting obesity and comorbid depression contemporaneously. Notwithstanding, the combination of CBT and lifestyle intervention show efficacy targeting obesity and comorbid depression as do some nutritional supplements, antidepressants and anti-diabetic agents.

LIMITATIONS

The high heterogeneity of various interventions in the included studies may cause a lack of comparability between different studies.

CONCLUSIONS

Concurrent management of depression and overweight/obesity is suggested by available data. There is a pressing need for studies that evaluate the effectiveness in real world samples of persons experiencing multiple co-occurring chronic diseases including but not limited to depression and overweight/obesity.

A Neuroeconomics Approach to Obesity

Obesity is a heterogeneous condition that is affected by physiological, behavioral, and environmental factors. Value-based decision making is a useful framework for integrating these factors at the individual level. The disciplines of behavioral economics and reinforcement learning provide tools for identifying specific cognitive and motivational processes that may contribute to the development and maintenance of obesity. Neuroeconomics complements these disciplines by studying the neural mechanisms underlying these processes. We surveyed recent literature on individual decision characteristics that are most frequently implicated in obesity: discounting the value of future outcomes, attitudes toward uncertainty, and learning from rewards and punishments. Our survey highlighted both consistent and inconsistent behavioral findings. These findings underscore the need to examine multiple processes within individuals to identify unique behavioral profiles associated with obesity. Such individual characterization will inform future studies on the neurobiology of obesity as well as the design of effective interventions that are individually tailored.