According to WHO, it is estimated that major depression would be the second most leading cause of disability in the world by 2020.Drug utilization study is defined as study of the marketing, distribution, prescription and use of drugs in a society highlighting on the resulting medical, social and economic consequences.The main objective of this study was to find the utilization pattern of antidepressants prescribed in a tertiary care centre with major depression in hospitalized patients of Western Nepal.A hospital based observational study was done between October 2009 and March 2010 at Psychiatry Ward of Manipal Teaching Hospital, Nepal.Both qualitative and quantitative data was collected from bed side.Depression was more common in housewives 42.1% followed by teachers 18.4% and students 10.5%. Fluoxetine was the commonest antidepressants to be prescribed 42.1% followed by Amitriptyline 26.3%, Trazodone 21.1% etc.This book also includes ATC codes,Drug utilization study, Classification of Drugs, Defined daily doses, History of Psychotropic drugs, History of Psychiatry in Nepal,Typical and atypical antidepressants,various theories of depression, lag period of antidepressants etc.