Prevalence of depression and anxiety in irritable bowel syndrome: A clinic based study from India - Comments on the article.

Sir,

It is with great interest that we read the article titled “prevalence of depression and anxiety in irritable bowel syndrome (IBS): A clinic based study from India.”[1] First we would like to appreciate the efforts of the authors in doing this kind of basic research in India. The straightforward methodology and use of standardized diagnostic criteria and rating scales will facilitate future studies along the same lines and would help comparison. As we read the paper the following questions came to our minds, which we raise here for the purpose of clarification so that readers can have a better understanding of the study findings.

The process of selection of 35 patients in each group leaves some queries unanswered. The authors mention that cases and controls were randomly selected but do not dwell on the randomization procedure employed if so. How many eligible patients had to be excluded from the study and for what reasons? Did any of the case subjects have a previous history of depression? This information would help in defining caseness in future studies and in framing appropriate inclusion and exclusion criteria

The use of nonulcerative dyspepsia[2] patients as control groups in this study is appreciated. However, the authors have not elaborated on how this diagnosis was arrived at. It also appears that no matching was attempted between the cases and controls. A high proportion of respondents with IBS were older females. It is conceivable that this may have contributed to the higher prevalence of mood symptoms among cases as opposed to controls

It is somewhat unusual to convert age into binary variable and the reason for using 35 years as the cut-off is unclear. It would aid understanding if the authors would explain their motives for doing so

The authors have provided limited information on socio-demographic characteristics of the sample. This assumes significance because some of the demographic findings noted in the IBS sample are at variance with what has been described in literature. An affluent upbringing has been consistently noted as a risk factor for IBS across studies,[34] whereas the authors found a significant proportion of their cases belonging to the lower socio-economic strata. That this figure differs significantly from the control group makes one wonder if different socio-cultural dynamics are at play in our setting in order to bring about the IBS syndrome

The authors have used validated rating scales like Hamilton depression rating scale[5] and Hamilton Anxiety rating scale.[6] However, we are curious to know whether those involved in measurement of outcomes were blinded to the case or control status of the participants. This has obvious implications in terms of interviewer bias, which may have influenced the results otherwise.

In summary, the study attempts to shed light on a hitherto unexplored area in India. The use of standardized rating scales and a control group lend a degree of credence to the findings. The wide confidence intervals for the effect sizes reported in the study could imply a small sample size. Future studies should be based in community settings with large samples in order to challenge the current dogma that increased psychological distress in out-patients with functional gastrointestinal disorders are largely explained by health-care seeking.[7]