The article under review was published in the 39th issue of the International Journal of Epidemiology in 2010, and it was written by two researchers from the North Carolina’s Duke University. The authors’ research problem is the link between physical and mental health, or, more specifically, the adverse impact that negative health events have on mental health (Mohanan & Maselko, 2010, p. 488). The authors set out to explore two research questions. First of all, they would like to estimate the causal effects of health shock on mental health. Secondly, they intend to examine how debt and disability may or may not serve as potential mediators in regard to the issue (Mohanan & Maselko, 2010, p. 487). According to the authors, the main advantage of their research is its quasi-experimental design that allows them to estimate causality between the two phenomena, which has been difficult to do in the past (Mohanan & Maselko, 2010, p. 488).
While the authors do not formulate a testable hypothesis, they do, nevertheless, have certain expectations as to the result of the study. They believe that, first of all, there is a causal relationship between health shocks and mental health-related issues. Secondly, they assume that household and disability, whenever they result from a negative health event, have a positive link to mental health and can thus serve as mediators of the causal relationship (Mohanan & Maselko, 2010, p. 488). Using a quasi-experimental quantitative research design, the authors confirmed that negative physical health events can cause long-term mental health problems. While they found that disability functions as a key mediating mechanism, no association between household debt and the relationship between physical shock and psychological distress was found (Mohanan & Maselko, 2010, pp. 490-491).
One drawback of the study is that it does not include an extensive or, at least, a sufficient literature review. At the same time, the introductory part of the paper briefly places the issue in its context and refers to several pieces of previous research to support the claims made in this section (Mohanan & Maselko, 2010, p. 488). Nevertheless, this section does not substitute a literature review because it appears that the information provided is rather scattered and used selectively. Thus, the authors do not engage with the material critically – that is, they do not consider the different sides of the argument and do not provide sufficient justification as to why they believe their stance is more noteworthy. However, it also appears that the article may have been shortened for the purpose of publication, and the original work includes a more well-developed literature review.
The research presented in the article is of particular relevance to current health issues. Discussion concerning mental health issues has gained particular salience and even momentum in the recent years, as the mainstream discourse seems to have accepted the need to acknowledge the problem and deal with it. From the medical standpoint, mental health issues, unfortunately, remain largely underexplored and, to a considerable extent, poorly understood. This research bears particular significance as it aims to establish and estimate a causal relationship between a specific event – that is, physical health shock – and mental health. Thus, such research makes an important contribution to the study of mental health issues.
As the name of the article suggests, the present paper utilizes a quasi-experimental research design. The authors offer two explanations for selecting this research type. First, given the nature of the research problem, other methods of analysis such as the ordinary least squares estimates tend to produce invariably biased outcomes. A quasi-experimental study design, on the other hand, tackles this issue as it combines experimental features with “exogenous variation in the exposure of interest.” Secondly, the authors note that previous epidemiologic research did not frequently employ such a method of study (Mohanan & Maselko, 2010, p. 488). Particularly, the authors look at two groups of respondents. People in the first group had a bus accident experience within the past year and sustained some physical injury as a result of it. The control group consisted of those individuals who had similar characteristics, also traveled on this route, but never got into an accident on it.
The sample selected for this study included 420 people from a rural region in India. All of them were regular passengers on the same bus route, except that 84 of them were exposed to a bus accident that resulted in a physical injury, whereas the remaining 336 respondents were unexposed. Thus, there is a 1-4 ratio between exposed and unexposed individuals, with the latter being selected in such a way as to ensure they are of the same age and gender and reside nearby the exposed passengers. The authors believe that the latter serves as a valid proxy for socioeconomic status, given the cultural peculiarities of the country. The information on the exposed individuals was retrieved from the government compensation records (Mohanan & Maselko, 2010, p. 488). Overall, it appears that the authors have selected an appropriate and effective sampling strategy, yet the size of the sample presents some concerns. Given the scope of the research problem, the findings of the paper may not be generalizable because of the sample size.
Since the research problem has especial relevance to the current health issues at a societal level, one would assume that the study should have important practical implications. While I do recognize the importance of research-based evidence in medicine, to me, the research results seem somewhat obvious and self-explanatory. Thus, the authors conclude that the rehabilitative measures intended to minimize physical injuries are likely to have a spillover effect of addressing the accompanying mental health issues, especially in the case of rapid onset conditions. Consequently, they emphasize the need to routinely conduct mental health screenings even for patients with non-psychiatric conditions (Mohanan & Maselko, 2010, p. 491). I believe that such measures should be, indeed, highly encouraged, so I realize that the study yields some significant practical implications. Apart from that, the article seems to have special theoretical and methodological weight, given its unconventional methodology design.
I think that the article could have been improved in two ways. First of all, I believe it would be highly beneficial for the authors to include a more comprehensive literature review. References to previously conducted research will give their work more credibility, and will help the audience place the issue in the relevant context. Secondly, the article in its current form raises some questions about the external validity of its findings, as the authors acknowledge themselves (Mohanan & Maselko, 2010, p. 492). For the research results to be generalizable, the study can be duplicated using a larger sample or, alternatively, using several internally consistent and valid samples.
Thus, the need to repeat the study using a different sample reveals that further research can and should be conducted on the subject. The authors also indicate several directions for future research in their article. Now that the existence of a causal relationship between mental health and physical injuries has been established, the medical research community needs to examine the particular details and features of this relationship. Apart from that, the authors encourage further policy-oriented research aiming to understand the spillover effect that physical rehabilitative measures can have in addressing the related mental health issues (Mohanan & Maselko, 2010, p. 492).
Finally, it is worth noting the writing style of the authors. Overall, the language they use is clear and straightforward and creates no difficulties for the reader to follow the article. The authors make an extensive use of field-specific medical terminology without defining it but, considering the article’s medium of publication, it should not come as a surprise. The authors are consistent in using the research-related vocabulary so that the audience can easily follow their arguments and understand the links and relationships between different concepts and phenomena that the authors discuss in their paper.
Thus, the present article is a methodologically rigorous and innovative study that makes a significant contribution to the existing medical knowledge by establishing the causal relationship between physical injuries and mental health. The data used for the study is reliable and internally consistent, and the authors designed an effective sampling strategy to make sure that they include a matching control group. The study yields important implications both for the research community and practitioners as it helps identify the strategies that may be effective in addressing the developing mental health problems in patients who have experienced a rapid onset physical injury. While the study does have its limitations, they can be successfully managed if the study is duplicated in the future.
References
Mohanan, M., & Maselko, J. (2010). Quasi-experimental evidence on the causal effects of physical health on mental health. International Journal of Epidemiology, 39, 487-493.