Comments on "Pattern and Correlates of Depression among Medical Students: An 18-Month Follow-up Study''.

Dear Sir,

As medical teachers and mental health professionals, we read this study with great interest. Although many previous studies have already reported a high level of stress and psychological morbidities in medical students, to our knowledge, this is the first study to longitudinally explore the above issue to assess the effect of the time spent in the medical course on the mental health status of medical students.[1] However, we opine that the following points should be considered while interpreting the results of this study.

The tool used in this study to detect depression, i.e., Patient Health Questionnaire (PHQ)-9 has 88% sensitivity and 88% specificity in cross-sectional designs, but its validity in longitudinal studies is yet to be established.[2] Among 348 medical students eligible for participation for this study, the assessment for depression could be completed in 325 (at 2 months), 279 (at 8 months), and 320 (at 18 months). It is important to know whether the characteristics of the students who dropped out at the second follow-up (8 months) and were available again at the last assessment (18 months) did differ significantly from those continued with the study at all the points of assessment.

While the use of substances other than alcohol, particularly cannabis, is common among professional course students, alcohol was the only substance investigated in this study. A recent survey conducted anonymously among students of a medical school in Kerala had found an increased use of cannabis among those diagnosed with mental health conditions.[3] Because the pattern of “use” of alcohol is not mentioned in the study, it is not possible to know whether it was more problematic (at abuse or dependence level) in those who had depression than those who did not have it.

This study assessed many socio-demographic and family-related variables, but not the family history of psychiatric illness, especially mood disorder. This information is more desirable, given the high prevalence of depression it found.

The authors have mentioned in the discussion part that the association of “unemployed mother” with the increased prevalence of depression in the students was due to financial difficulties of the family. We don't agree with the above explanation as the study has not found any significant association of “student loan” with depression. Therefore, we propose an alternative explanation that it is a type 1 error because of the many variables included and the absence of statistical correction.

To conclude, we appreciate the efforts of the investigators. However, certain issues, as mentioned above, need to be considered while planning similar studies in the future.

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Conflicts of interest

There are no conflicts of interest.