Obesity is a leading global epidemic. Bariatric surgery is the only treatment demonstrating substantial long-term weight loss and medical benefits. However, there is limited research on the psychological outcomes following surgery.Therefore, the primary aim of this study was to systematically review depression, anxiety, and binge eating outcomes at different time points following bariatric surgery and identify whether bariatric surgery significantly reduces psychological symptoms over time. These outcomes were also examined among endoscopic bariatric procedures as a secondary aim. Forty-eight studies met inclusion criteria.

Ranked highly in its association with serious medical comorbidities, obesity, a rapidly growing epidemic worldwide, poses a significant socioeconomic burden. While bariatric procedures offer the most efficacious treatment for weight loss, a subset of patients risk weight recidivism. Due to the heterogeneity of obesity, it is likely that there are phenotypes or subgroups of patients that require evidence-based psychological support to produce more sustainable outcomes. So far, however, characteristics of patients have not led to a personalized treatment algorithm for bariatric surgery. Maintenance of weight loss following bariatric surgery requires long-term modification of eating behaviors and physical activity. A recent Clinical Obesity Maintenance Model (COMM) proposed a conceptual framework of salient constructs, including the role of habit, behavioral clusters, emotion dysregulation, mood, health literacy, and executive function as interconnected drivers of obesity maintaining behaviors relevant to the field of bariatric psychology. The primary aim of this concise review is to bring together emerging findings from experimental and epidemiological studies relating to the COMM constructs that may inform the assessment and follow up of bariatric surgery. We also aim to explain the phenotypes that need to be understood and screened prior to bariatric surgery to enable better pre-surgery intervention and optimum post-surgery response.

In recent years, with the emergence of relatively inexpensive and accessible virtual reality technologies, it is now possible to deliver compelling and realistic simulations of human-to-human interaction. Neuroimaging studies have shown that, when participants believe they are interacting via a virtual interface with another human agent, they show different patterns of brain activity compared to when they know that their virtual partner is computer-controlled. The suggestion is that users adopt an “intentional stance” by attributing mental states to their virtual partner. However, it remains unclear how beliefs in the agency of a virtual partner influence participants’ behaviour and subjective experience of the interaction. We investigated this issue in the context of a cooperative “joint attention” game in which participants interacted via an eye tracker with a virtual onscreen partner, directing each other’s eye gaze to different screen locations. Half of the participants were correctly informed that their partner was controlled by a computer algorithm (“Computer” condition). The other half were misled into believing that the virtual character was controlled by a second participant in another room (“Human” condition). Those in the “Human” condition were slower to make eye contact with their partner and more likely to try and guide their partner before they had established mutual eye contact than participants in the “Computer” condition. They also responded more rapidly when their partner was guiding them, although the same effect was also found for a control condition in which they responded to an arrow cue. Results confirm the influence of human agency beliefs on behaviour in this virtual social interaction context. They further suggest that researchers and developers attempting to simulate social interactions should consider the impact of agency beliefs on user experience in other social contexts, and their effect on the achievement of the application’s goals.

In recent years, with the emergence of relatively inexpensive and accessible virtual reality technologies, it is now possible to deliver compelling and realistic simulations of human-tohuman interaction. Neuroimaging studies have shown that, when participants believe they are interacting via a virtual interface with another human agent, they show different patterns of brain activity compared to when they know that their virtual partner is computer-controlled. The suggestion is that users adopt an "intentional stance" by attributing mental states to their virtual partner. However, it remains unclear how beliefs in the agency of a virtual partner influence participants' behaviour and subjective experience of the interaction. We investigated this issue in the context of a cooperative "joint attention" game in which participants interacted via an eye tracker with a virtual onscreen partner, directing each other's eye gaze to different screen locations. Half of the participants were correctly informed that their partner was controlled by a computer algorithm ("Computer" condition). The other half were misled into believing that the virtual character was controlled by a second participant in another room ("Human" condition).Those in the "Human" condition were slower to make eye contact with their partner and more likely to try and guide their partner before they had established mutual eye contact than participants in the "Computer" condition. They also responded more rapidly when their partner was guiding them, although the same effect was also found for a control condition in which they responded to an arrow cue. Results confirm the influence of human agency beliefs on behaviour in this virtual social interaction context. They further suggest that researchers and developers attempting to simulate social interactions should consider the impact of agency beliefs on user experience in other social contexts, and their effect on the achievement of the application's goals.PeerJ Preprints | https://doi.org/10.7287/peerj.preprints.3018v1 | CC BY 4.0 Open Access |

Research from high-income countries has shown that grazing is a common but problematic eating pattern, particularly when associated with a sense of loss of control. However, it is unclear whether these patterns hold globally. Thus, the goal of this study was to extend previous research by examining the prevalence and clinical correlates of compulsive grazing (CG) and non-compulsive grazing (NCG) in a middle-income country. Participants (N = 2297) comprised adult residents from Rio de Janeiro, Brazil. Recruitment of this population-based household survey occurred from September 2019 to February 2020. The short inventory of grazing was used to operationalise grazing subtypes. Chi-square analyses, logistic regression, and univariate tests were conducted using the complex samples procedure. The point prevalence of regular CG was 10.2% (n = 239) and was consistent with high-income countries, while NCG was 29.8% (n = 679) and was less frequent than reported in high-income countries. Additionally, similar to high-income countries, CG was associated with a higher body mass index and higher odds of eating disorders, eating disorder symptomatology, depression, anxiety, and a lower physical and mental health-related quality of life, than no grazing and NCG. Overall, this study demonstrated that grazing patterns in high-income countries extend to middle-income countries.