We discuss the brain mechanisms behind depression. Paula Kaanders and Lukas Krone talk to Prof Catherine Harmer from the Department of Psychiatry about her work on emotional processing in depression and the latest developments in understanding and treating depression. We also talk about Catherine's career path and her advice to graduate students. Creative Commons Attribution-Non-Commercial-Share Alike 2.0 UK: England & Wales; http://creativecommons.org/licenses/by-nc-sa/2.0/uk/