INTRODUCTION

According to the classification of mental and behavioral disorders included in the International Classification of Diseases (ICD-10), it is observed that patients with anxiety and depression disorders may present a clinical picture of anxiety associated with depressive symptoms, without a clear predominance between both and at the same time that the intensity of one does not allow the other to be diagnosed in isolation¹. The evidence on this clinical simultaneity considers the common fact that these pathologies are commonly related to dysregulation in neurotransmitters such as serotonin, among other factors. In both clinical situations, it is possible to observe the presence of subsyndromal symptoms with hyperactivity of the autonomic nervous system, gastrointestinal complaints, tremors and palpitations².

It has been proposed that major depressive disorder is characterized by depressed mood for most of the day, decreased interest or pleasure in daily activities, significant weight loss or gain or reduced or increased appetite, insomnia or hypersomnia, agitation or psychomotor retardation, fatigue or loss of energy, feelings of worthlessness or guilt, indecision or loss of ability to concentrate, recurring thoughts of death, suicidal ideation or attempted suicide for a period of two weeks. Generalized anxiety disorder is identified by the presence of restlessness or a feeling of being on edge, fatigue, difficulty concentrating or sensations of “blank” in the mind, irritability, muscle tension and sleep disturbance lasting six months or more³.

Considered as one of the risk factors for the incidence of the aforementioned psychiatric disorders, obesity may be associated with compulsive behaviors, sleep disorders, in addition to cardiovascular diseases. This change in weight can be classified by evaluating the body mass index (BMI), into: overweight between 25 and 29.9kg/m², class I obesity between 30 and 34.9kg/m², class II obesity between 35 and 39.9kg/m² and class III obesity above 40kg/m². It is known that the more severe the obesity, the more compromised the quality of sleep will be and that this relationship can strongly contribute to the occurrence of anxiety and depression disorders, in such a way that for every hour of sleep deprivation there is a risk of psychological distress increased by 14% in obese individuals. This fact corroborates the subsequent intense weight gain due to the reduction in satiety and the rate of basal metabolism associated with the decrease in the secretion of the thyroid-stimulating hormone leptin⁴,⁵.

There is evidence that estimates regarding the presence of obesity in the Brazilian population are around 18.9% and 13% of the world population. That is why it has been considered one of the main chronic non-communicable diseases (NCDs)⁶. At the same time that anxiety disorders make up one of the most common groups of psychiatric pathologies, with the American Comorbidity Study reporting that one in four individuals meets the diagnostic criteria for an anxiety disorder, with a rate of prevalence of 17.7% in 12 months, with women having a lifetime prevalence of 30.5% and men having 19.2%. Furthermore, the lifetime prevalence rate of major depressive disorder is five to 17%. However, it is postulated that the quantification of the relationship between anxiety and depression disorders in obese people is negatively affected due to the need for more expanded diagnostic studies².

Given the social and clinical relevance of the facts highlighted and based on the reported knowledge, we chose to carry out the present scope review study with the aim of the analyze the evidence on the prevalence of anxiety and depression disorders in obese patients.

METHODS

This is a scope review of the literature of cross- sectional studies on the prevalence of anxiety and depression disorders in obese individual. In order to guarantee as much as possible the methodological rigor necessary for evidence-based health practice, the present study was developed based on the recommendations of the instrument called PRISMA-ScR (Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews checklist)⁷, with the exception of those items relating to the stages of the data meta-analysis process.

This scope review was structured by the research question, elaborated based on the acronym PVO⁸, consisting of the terms: ‘obese individuals’ (P – patients or population under study), ‘psychological disorders of anxiety and/or depression’ (V – dependent qualitative variables) and ‘prevalence’ (O – outcome, to be identified), and configured as follows: What is the scientific evidence on the prevalence of anxiety and depression disorders in obese individuals.

From this research question, key words were extracted and scientific descriptors identified, together with the DeCS Terms system (http://decs.bvs.br/) and MeSH Database of the National Library of Medicine (https://www.ncbi.nlm.nih.gov/mesh/): ‘obesity’, ‘anxiety disorders’ and ‘depressive disorder’. Which were used in the Boolean systematic search carried out on 17/01/2023 in the databases PubMed (Medline), Web of Science and Scopus, as follows: (‘obesity’ AND (‘anxiety disorders’ AND ‘depressive disorder’)). In order to make the investigation more focused on the objectives of the present study, the searches were limited by the following filters: studies carried out in humans, published between 2002 and January 2023.

Prior to the process of searching for scientific documents in the databases, this study was registered (ID: CRD42023388776) together with the international database of records of literature review protocols called PROSPERO (https://www.crd.york.ac.uk/prospero/), with the objectives of avoiding duplication of studies on the chosen topic, providing total transparency about the preparation method, as well as expanding the capacity to improve the study depending on the opinion to be issued by the team of evaluators⁹. To this end, eligibility criteria for inclusion and exclusion of scientific documents for data collection were established prior to paired evaluations, in accordance with literary recommendations¹⁰,¹¹. As stated in the protocol registration statement sent by the PROSPERO team, there were no recommendations for changes in the process of preparing this review study.

Cross-sectional studies carried out in humans, without gender restrictions and independent of language, were included. Provided that the scientific study has been, prior to its completion, approved by a research ethics committee as it is in accordance with the ethical principles of confidentiality, non-maleficence and autonomy. As parameters for exclusion, the following aspects were considered: content not converging with the objectives of this review; those in which participants had previously undergone some type of therapeutic intervention, such as bariatric surgery or patients in the gestational period; in addition to considering divergences related to the inclusion criteria.

All articles found in the different databases were gathered in the virtual environment using the citation manager application, called Rayyan QCRI – Quatar Computing Research Institute¹², through which the identification and elimination of duplicates and eligibility steps for each document were carried out in pairs.

The information for each stage of the article eligibility process was shown in the eligibility flowchart, figure 1, while the data relating to the aspects: literary, clinical-instrumental and analytical, were shown in tables 1, 2 and 3, respectively. The sociodemographic characteristics of participants in the different studies were also described in the results section.

Figure 1 Eligibility flowchartSource: prepared by the authors. 

The paired assessment of the methodological quality or risk of bias of the included articles was carried out using the Critical Assessment of Studies with Prevalence Data tool (CASPD-JBI), developed by the Joanna Briggs Institute (JBI) study group, which is composed of nine items that evaluate everything from the sample structure of the included study to the outcomes, and each item must be given an adjective such as: yes, no uncertain or not applicable¹³. This assessment is of great importance for checking the respective levels of reliability of the evidence generated in the studies¹⁴. The data evaluating methodological quality were shown in figure 2, located in the results section of the present study.

Figure 2 Evaluation of methodological quality or Risk of Bias. Source: prepared by the authors. 

We emphasize that both the eligibility and data extraction process, as well as the aforementioned evaluations, were carried out in pairs between the participants of the research team under the supervision of the researcher responsible for the study. Any situations involving doubts or differences in decision-making between the evaluators were resolved through the intervention of the responsible researcher, to promote the necessary conditions for consensual decision-making. In order to obtain a better index of intra-examiner and inter-examiner agreement, the team of evaluators was properly calibrated as they had previously undergone the process of clarification and operational training on the aforementioned evaluation tools, as recommended in the literature¹¹.

RESULTS

According to the data shown in the eligibility flowchart (figure 1), we observed that through the Boolean search, 30 articles were located, among which no duplication was identified. After their paired evaluation, based on the eligibility criteria, 21 articles were excluded, among which: 13 were excluded because they were different types of studies and/or were not related to the objectives of the present study, and another 8 were excluded because they were observational studies carried out on participants who had undergone some type of intervention, especially bariatric surgery. Thus resulting in a literary sample of nine articles, from which data converging with the objectives of the present study were extracted (figure 1).

Using information on age, sex and total number of participants identified in the included studies, we observed that among the approximate total of 5,691 + 1071 participants constituting the ‘N sample’ in the present scoping review study, 64.26% + 19 .74 were female and the other 35.74% + 20.00 were male, both with an average age equivalent to 29.99 + 10.79 years, despite the existence of some participants aged 16 and also 67 years old.

According to the data on literary aspects shown in table 1, we can observe that although the period proposed for collecting data related to the present study in the aforementioned databases was 21 years, the publication dates of the included studies are distributed over only 1/3 of this period as follows: 2002 (1), 2006 (1), 2015 (1), 2016 (2), 2019 (1), 2022 (1), 2023(2). Of the nine studies, four (36%) were conducted in Brazil, two (18%) in Mexico, while each of the other three were conducted respectively in Italy, Sweden and the United States of America.

According to the data shown in part 1 of table 2, a prevalence of coexistence of anxiety and depression disorders was observed in participants with different degrees of obesity, in eight of the nine selected articles, and in the ninth study the presence of depression was identified while anxiety was not assessed by the authors.

In relation to the data in part 2 of table 2, there was no identification of the assessment instruments (AI) used for diagnostic identification of the aforementioned psychological disorders in two of the nine selected articles (A8 and A9). In the others, five instruments were used to assess anxiety, distributed per article as follows: Hospital Anxiety and Depression Scale (HADS) - (n=2), Mini international neuropsychiatric interview - (MINI) (n=2), Diagnostic and Statistical Manual of Mental Disorders - DSM-5 criteria (n=1), Structured Clinical Interview for the Diagnostic and Statistical Manual of Mental Disorders DSM-5 (n=1) and State - Trait Anxiety Inventory (STAI) - (n=2). To assess depression, three of the five AIs used for anxiety diagnoses were used, in addition to three other AIs. The distribution of these AI by articles was as follows: HADS (n=2), MINI (n=2), DSM-5 (=1) and DSM-5/SCID-5-CV (n=1), Beck Depression Inventory (BDI) - (n=1), BDI-II (n=1), and Center for Epidemiologic Studies Depression Scale Revised (CESD-R) (n=1).

According to the outcome data shown in table 3, it is possible to observe that, in all the studies gathered in the present review, obese individuals had a constant presence of symptoms related to the psychological disorders of anxiety and depression, at varying levels of prevalence, with degrees of severity that ranged from mild to severe symptoms, whether or not associated with binge eating disorder, in a fairly homogeneous way between men and women. The presence of other health problems is also identified, such as discomfort in relation to one’s own body image, low self-esteem, respiratory problems, systemic arterial hypertension, sleep disorders and the presence of pathologies of the musculoskeletal system.

Regarding the aspect of the methodological quality or risk of bias of the studies gathered in this review, it can be seen, as shown in figure 2, that 56% of the included studies were assessed as having high methodological quality, while 44% were considered to have moderate methodological quality due to the presence of one or more attribution of an ‘uncertain’ opinion in relation to any of the assessment items. In such a way that none of the studies were evaluated with low methodological quality.

DISCUSSION

A possible bidirectional relationship between the physiological and psychological causal issues involved with obesity has been widely postulated in the literature⁵,²⁴,²⁵,²⁶,²⁷,²⁸,²⁹,³⁰. This causal interrelationship was notable in patients with anxiety and depression disorders who became obese, or in patients with obesity associated with psychiatric components. The dysregulation of the homeostasis of satiety centers can be considered one of the basic causes of obesity, manifested mainly in the form of binge eating as food becomes a compensatory means to deal with emotional stress, culminating in excessive weight gain.

Another contributing factor is the loss of homeostasis of brain reward feedbacks, including lower secretion of leptin and thyroid-stimulating hormone, which results in irregular eating patterns, malaise, sedentary lifestyle and caloric surplus, resulting in the maintenance of obese conditions⁵,²⁷,²⁸. Furthermore, especially in situations of chronic stress present in obese individuals, hypercortisolemia may be associated with psychiatric disorders.

This complex interaction between physiological and psychological aspects highlights the importance of a holistic approach in the treatment of obesity and its relationship with mental health. By understanding these connections, healthcare professionals can develop more effective strategies to help patients address the challenges associated with obesity and psychiatric disorders²⁸,²⁹.

In addition to the data gathered in the present review pointing to the presence of serious mental health problems in individuals with severe obesity¹⁵,¹⁶, they also demonstrate that binge eating disorder (BED) is a highly prevalent component in obese people with comorbidities psychiatric¹⁷,¹⁸,²⁰,²².

The decline in mental health in obese individuals may be significantly related to body weight stigma, which results in society’s prejudiced conception of these individuals, which negatively qualifies them regarding self-care and willpower. In this way, it contributes to the development of low self-esteem and self-depreciation, which can evolve into anxiety and/or depression²⁴,²⁷,²⁸. In such a way, issues related to concerns about body image constitute triggers for periodic compulsive eating disorder, especially in individuals with class III obesity, as pointed out in this review¹⁸.

Given this, in order to obtain good prognoses for the treatment of these cases, it is clear that weight control for such people should cover not only the energy values of food, but also the need for emotional regulation. However, even though improved mental health has been described as a positive factor in reducing excess weight, there is still a lack of appropriate psychological support to make this relationship a reality²⁴,²⁵,²⁶,²⁷,²⁸,²⁹,³⁰. Therefore, according to data highlighted in this review, it is imperative that there is an alert to the general population about the importance of breaking stigmas and how this influences the mental health of others, as well as emotional support through therapies for those who are affected¹⁵,¹⁶,¹⁷,¹⁸,¹⁹,²⁰,²¹,²²,²³.

Even though we have consistently identified the coexistence relationship between anxiety and depression disorders in obese people, we infer as a methodological weakness of the present study, the possible need to carry out an expanded search for documents in other databases. In this way, it would be possible to cover a larger universe of publications to try to detail the subject in more detail about the prevalence of the aforementioned psychiatric disorders in obese people, as well as other forms of semiological approaches. In addition to the fact that such a procedure could possibly increase the geographic scope of studies carried out in several other countries.

At the same time, based on the evidence from this study, we suggest that clinical approaches to obese patients are structured not only to reduce body weight, but also to address commonly present psychopathological issues. A fact that requires more comprehensive and precise diagnostic mechanisms, associated with intervention strategies consistent with the biopsychosocial character of these patients existential complexity.

CONCLUSION

Although more studies with greater methodological rigor are still needed, we consider that the concomitant prevalence of anxiety and depression disorders is high in patients with different levels of obesity, especially in those with severe obesity. This suggests the inclusion of the evaluation of these psychological disorders in the evaluation portfolio of obese people, for a better therapeutic approach.