Introduction
A psychological research study focuses on how humans think and behave. The study may involve manipulating one or more factors to find their impact on the dependent variable. The person in question uses the independent element of a certain variable if it impacts the dependent variable.
The research “Relationship of Depression, Anxiety, and Bipolar Disease with Burning Mouth Syndrome: A Nationwide Cohort Study” by Lee et al. examined the connections between bipolar illness, burning mouth syndrome (BMS), anxiety, and depression. The existence or absence of bipolar illness, anxiety, or depression was the study’s independent variable. The study used a cohort of individuals living in Taiwan who received a BMS diagnosis between 2000 and 2010. 14,408 BMS patients and 57,632 BMS-free control patients were enrolled in the study (Ross & Grant, 2019). The connection between BMS and depression, anxiety, and even bipolar disorder was evaluated using a Cox proportional hazards regression analysis to obtain risk ratios (HRs) along with 95% confidence intervals (CIs).
Aspects Increasing the Study’s Internal and External Validity
Several factors improved the research’s internal as well as external reliability. First off, the study’s use of a countrywide group helped the results be more broadly applicable. Second, a control group with similar characteristics was included in the study to lessen the influence of confounding factors. Thirdly, the accuracy of the diagnosis was improved by using a verified diagnostic code by the researchers to recognize patients with BMS (Ross & Grant, 2019). Finally, to improve the study’s validity, the researchers adjusted for potential confounding factors such as age, sex, and comorbidities.
Bias Sources
This study contained various bias-producing factors. First off, the study’s method of identifying individuals with anxiety, depression, and bipolar disorder—patient identification through electronic medical records—may not have included all instances of these diseases. Second, the research did not account for drug use, which might have impacted the emergence of BMS. Last but not least, the study did not evaluate the degree of severity of BMS, which would have affected the connection with bipolar illness, anxiety, and depression.
Conclusion
In conclusion, “Relationship of Depression, Anxiety, and Bipolar Disorder with Burning Mouth Syndrome: A Countrywide Cohort Study” examined the link between BMS and depression, anxiety, and bipolar illness. Due to its use of a countrywide cohort, a matching control group, a verified diagnostic code, and confounding factor adjustment, the study had high internal and external validity (Ross & Grant, 2019). The utilization of electronic medical records, the absence of control over drug use, and the severity of BMS were all sources of bias.
Reference
Ross, A. S., & Grant, M. (2019). Manipulating the independent variable. Experimental and Nonexperimental Designs in Social Psychology, 44–57. Web.