Limitations
IBS, sleep disorders, IBS-C, IBS-D
The most important limitation of our trial was not classifying the sub-types of IBS (IBS-C or IBS-D), which probably affected the results of the "Frequency of defecations per week" parameter. Adherence to the trial was evaluated based on the patient's statements so that all patients stated that they adhered to the trial, and no patients were excluded from the trial for this reason. Another limitation was using questionnaires to evaluate the parameters because some patients may not be accurate enough or even exaggerate when answering the questions; so, using other methods, such as polysomnography, could give more accurate data instead of a questionnaire to determine sleep disorders. For a definite conclusion as well as the optimal drug dose, patients who benefit the most from this treatment, and long-term effects of melatonin, it is recommended conduct more trials with a larger sample size in which patients are classified into IBS subtypes, in a more extended period of trial using objective methods than questionaries.