Beckground: Depression is a state of low mood and aversion to activity that can affect a person‘s thoughts, behaviour, feelings and sense of well – being. Depression is a major cause of disability worldwide. Various studies demonstrated the efficacy of antidepressant drugs by using various rating scales available to measure the depth of severity of depression. e.g. Hamilton Depression Rating Scale , Montgomery–Asberg Depression Rating Scale, Raskin Depression Rating Scale,  Beck Depression Inventory (BDI), Geriatric Depression Scale (GDS), Zung Self–Rating Depression Scale and Patient Health Questionnaire (PHQ) sets etc. BDI is one of the most widely used instruments for measuring the severity of depression.

Method: This open label, prospective and observational study was conducted to evaluate the efficacy of imipramine, sertraline and escitalopram in major depressive patients. DSM –V criteria was used to diagnose the depressive patients. A total of 810 such patients were randomly divided into three groups i.e. group I, II & III containing 270 patients in each group. Patients of these groups were treated with imipramine, sertraline and escitalopram respectively as per schedule dose. Base line parameter such as heart rate, blood pressure and BDI score were recorded and follow up at 4, 8 and 12 weeks. Data were analyses with appropriate statistical methods.

Results: We found that female patients were more than male. A total of 187 patients in group I, 228 in group II and 237 patients in group III completed this study. During study period, all the three groups showed a significant increase in mean values of heart rate as ‘p’ values are less than 0.05. However in groups; mean value were within normal range at all followup intervals. A total of 9 patients were drop out in imipramine group due to tachycardia whereas it was 6 and 4 in sertraline and escitalopram group respectively. In all groups systolic as well as diastolic BP was progressively increased at 4, 8 and 12 weeks but it was within normal range. Group III showed maximum efficacy whereas it was minimum with group I after 12 weeks of treatment.

Conclusion: Escitalopram showed maximum efficacy whereas imipramine possess least after 12 weeks of treatment. Response rate of escitalopram and imipramine was almost similar whereas it was seen least with imipramine, so overall escitalopram was found better than sertraline and imipramine.