Abstract
Aim
The study aims to conduct an integrative review synthesizing and interpreting existing research results on the interrelation between these two types of disorders.
Background
Obesity is a serious chronic disease that complicates the functioning of internal organs, leads to other serious diseases, and negatively affects the quality of life in general. At the same time, direct medical costs for obesity in the United States are estimated at $ 92.6 billion, ranging from 5.5 to 9.1% of total healthcare costs (Lee et al., 2018). A review of existing research will help develop a more detailed and targeted formulation of policies on different levels to improve the epidemiological situation with obesity and, accordingly, reduce health care costs in this area.
Design and data sources
Studies for further analysis were searched for in the PubMed and Cochrane Library databases using a combination of keywords most relevant to the research question. The inclusion criteria were peer-review journals and articles reporting the findings related to the research question, i.e., answering the question about the interrelation between obesity and mental health.
Review Method
A five-stage integrative review method includes the formulation of the problem, the search in the databases, evaluation and processing of the initial sample, synthesis of the final sample, and an evidence table.
Results
The research supports the hypothesis about a statistically significant correlation between various mental issues and obesity. Most of all, this applies to depression and anxiety disorder.
Conclusion
The integrative review of the existing literature demonstrates that there is strong evidence supporting the existence of the association between obesity and mental disorders. At the same time, their causal relationships are bidirectional, which strengthens the first statement. In practice, it would mean that decision-makers would need to address mental health to lower the costs of population health-related to obesity.
Introduction
Background. Obesity is a huge social problem and has become an epidemic in recent years. In the United States, as of December 2020, more than 42% of the adult population was obese (Anekwe et al., 2020). Obesity significantly increases the risk of developing other chronic diseases and serious conditions, including type 2 diabetes and cardiovascular disease, as well as some types of cancer (Anekwe et al., 2020). Being overweight also significantly increases the risk of developing severe complications from coronavirus infection (Buscemi et al., 2020). All this places a heavy burden on the healthcare system since the cost of care for patients with cardiometabolic disorders associated with obesity is significantly higher than for patients with normal body weight (Anewke et al., 2020). Studies evaluating the cost of treatment for obesity show that obesity contributes to a significant increase in overall treatment costs (Lee et al., 2018). Direct medical costs for obesity in the United States are estimated at $ 92.6 billion, ranging from 5.5 to 9.1% of total healthcare costs (Lee et al., 2018). In addition to physical health problems, obesity is also associated with a high risk of developing mental problems. At the same time, it is argued that existing mental disorders can lead to eating disorders, including obesity. Given the various existing studies related to the interrelation between obesity and mental health, there is a need for a comprehensive literature review to assess and summarize it.
Thus, the aim of the study is to conduct an integrative review synthesizing and interpreting the results of existing research on the interrelation between these two types of disorders. The research question is: “Is there a significant correlation between obesity and mental health and, if yes, what is the causal relation between them?” The answer to this question will help to develop a more detailed and targeted formulation of policies on different levels aimed at improving the epidemiological situation with obesity and, accordingly, reducing health care costs in this area. The dependency of the variables varies: in the studies, which will state the previously existing mental disorder and subsequent obesity, the former will be an independent variable, and the latter will be a dependent one. In the research focusing on obesity leading to mental disorders, the variables will transform vice-versa.
Literature Search
Design and Data Sources. A systematic literature review was conducted using the PubMed and Cochrane Library electronic health information databases. The keywords used for the publications search were: obesity & mental disorder, “obesity” & ”mental disorder”, obesity & depression, “obesity” & “depression”, obesity & anxiety, “obesity & anxiety”, obesity & mental health, “Obesity” & “mental health”, obesity & psychiatric disorders. “Obesity” & “psychiatric disorders”.
When searching, it was indicated that the keywords should be found in the title, abstract, and/or the text field of the article. The articles no older than five years were reviewed to narrow the research and limit the evidence to the up-to-date results (starting from 2016). The inclusion criteria were peer-review journals and articles reporting the findings related to the research question, i.e., answering the question about the interrelation between obesity and mental health. The articles not focusing on this problem were excluded from the review. Another exclusion criterion was the absence of data (for example, “manifest” articles). Thus, the final sample consisted of six peer-reviewed articles of 2016 and later presented statistically significant precise findings of the research dealing with the interrelation between obesity and mental disorders and their causal relations.
Methodology Analysis
Review method. The research comprises a five-stage integrative review method. First, the problem and the research question were formulated. Second, the evidence-based medical databases (Pubmed and Cochrane library specifically) were used to search for reliable peer-review articles stating the research findings focusing on the stated problem. The specific keywords were used to obtain the results of the search. Third, the general sample was evaluated and processed. Fourth, the final sample was analyzed, synthesized, and interpreted. Finally, the results were formulated in a concise evidence table.
The final sample of the articles analyzed was appropriate for the research question and hypothesis since it combined both systematic and/or meta-reviews and specific research findings. The latter used statistical analysis, which included descriptive statistics and logical regressions. Also, the Pearson calculations, t-tests, Mann-Whitney U tests, and chi-square tests were employed to analyze specific research questions.
The main gap in the sample is that the literature mainly focuses on studying the links between obesity and depression or anxiety disorders, thus dismissing a variety of other mental disorders which might influence obesity as well. This gap might exist because the research findings target the outpatient population with the most common mental health disorders. At the same time, however, a significant inconsistency across literature lies in the fact that different researchers and research teams can conclude about depression’s existence based on different criteria.
Synthesis and Interpretation
Results. The final sample consisted of literature reviews and specific research dealing with the association between obesity and mental disorders. Thus, the research assessed utilized secondary data and original research. However, disregarding the difference in research quality, the studies seconded and supported each other in terms of results. In general, the research supports the hypothesis about a statistically significant correlation between various mental issues and obesity. Most of all, this applies to depression and anxiety disorder.
The literature reviewed also demonstrates a bidirectional causal link between obesity and mental illness. For example, Fox et al. (2016) determined that obese people with depression are 3.5 times more likely to develop severe obesity than those without partially due to emotional eating. Similarly, Lincoln (2020) supports these findings suggesting that obese people who suffer from stress, lead an unhealthy lifestyle, eat junk food, and are not satisfied with their bodies are more likely to develop a related psychiatric disorder. Thus, obesity is likely to be caused by mental instability. At the same time, the association may arise vice versa. For example, Weinberger et al. (2018) demonstrate that personal appearance evaluation among obese people is likely to cause depressive symptoms. Following statistical analyses, researchers reveal that both men and women tend to be unsatisfied with their appearance, which positively correlates with depression. Besides, the meta-review of longitudinal and cross-sectional observational studies conducted by Sutaria et al. (2019) adds to these findings since it establishes the influence of obesity on developing mental issues among children. Moreover, the review of Rajan and Menon (2017) indicates that psychiatric disorders and obesity, especially ED and depression, are closely linked and have a bidirectional relationship. The reviewed studies demonstrated two primary mediators influencing the development of mental disorders from obesity: victimization (Van Vuuren et al., 2019) and personal appearance evaluation (Weinberger et al., 2018). Although these findings bear crucial importance to understanding the causal link between obesity and mental disorders, future research is needed to address other mediators that lead to different mental disorders.
Ethical Concerns. The sample studies were conducted following all national and international ethical standards. Studies were not supported by third parties that stood to gain financially from the results of the research.
Conclusion
Strengths. The studies’ strengths are their aim to go beyond finding the correlation between obesity and mental disorders and study its causal relationships. The original studies focused on analyzing and outlining potential mediators, whereas the literature reviews demonstrated existing results on the topic.
Limitations. The main inconsistency prevalent in this stream of research is the absence of generally accepted definition and measurement tools of mental disorders. At the same time, the studies predominantly focused on the most common disorders – depression and anxiety.
Validity and Reliability. The Level of evidence in each study was reviewed for validity and reliability. The strongest LOE for this research was a meta-analysis, and the weaker studies were primarily qualitative reviews. Although the sample studies’ results supported each other, further consistent research is needed to ensure external validity since the age groups, sociodemographic characteristics, and research questions varied.
Implications. The integrative review of the existing literature demonstrates that there is strong evidence supporting the existence of the association between obesity and mental disorders. At the same time, their causal relationships are bidirectional, which strengthens the first statement. In practice, it would mean that in order to lower the costs of population health-related to obesity, decision-makers would need to address mental health as well.
References
Anekwe, C. V., Jarrell, A. R., Townsend, M. J., Gaudier, G. I., Hiserodt, J. M., & Stanford, F. C. (2020). Socioeconomics of obesity. Current Obesity Reports, 1-8.
Buscemi, S., Buscemi, C., & Batsis, J. A. (2020). There is a Relationship Between Obesity and Coronavirus Disease 2019 but More Information is Needed. Obesity, 28(8), 1371-1373.
Fox, C. K., Gross, A. C., Rudser, K. D., Foy, A. M., & Kelly, A. S. (2016). Depression, anxiety, and severity of obesity in adolescents: is emotional eating the link?. Clinical Pediatrics, 55(12), 1120-1125.
Lee, S. M., Choi, I. S., Han, E., Suh, D., Shin, E. K., Je, S.,… & Suh, D. C. (2018). Incremental treatment costs attributable to overweight and obesity in patients with diabetes: quantile regression approach. Obesity, 26(1), 223-232.
Lincoln, K. D. (2020). Race, obesity, and mental health among older adults in the United States: A literature review. Innovation in Aging, 4(5), 1-10. Web.
Rajan, T. M., & Menon, V. (2017). Psychiatric disorders and obesity: a review of association studies. Journal of Postgraduate Medicine, 63(3), 182-190. Web.
Sutaria, S., Devakumar, D., Yasuda, S. S., Das, S., & Saxena, S. (2019). Is obesity associated with depression in children? Systematic review and meta-analysis. Archives of Disease in Childhood, 104(1), 64-74. Web.
Van Vuuren, C. L., Wachter, G. G., Veenstra, R., Rijnhart, J. J., Van der Wal, M. F., Chinapaw, M. J., & Busch, V. (2019). Associations between overweight and mental health problems among adolescents, and the mediating role of victimization. BMC Public Health, 19(1), 1-10. Web.
Weinberger, N. A., Kersting, A., Riedel-Heller, S. G., & Luck-Sikorski, C. (2018). The relationship between weight status and depressive symptoms in a population sample with obesity: the mediating role of appearance evaluation. Obesity Facts, 11(6), 514-523. Web.
Appendix A
Table 1. Summary Evidence Table.