The study's primary goal is to assess the effectiveness of behavioural activation in reducing depressive symptoms and re-integrate patients with depression into their personal and professional lives thus improving quality of life and helping in attaining and maintaining remission of depression. It is aimed at helping patients re-engage with several life areas that they may have lost in the course of depressive illness. The intervention is centred on behavioural activation (BA) with complementary interventions including recreation activities, and behavioural modifications. The study question is: in patients with depressive disorder attending a specialized hospital based mood disorders clinic, does the addition of behavioural activation program delivered in a group format improve depressive symptoms and quality of life compared to treatment as usual after 18 weeks of treatment? Study investigators hypothesize that behavioural activation is an effective treatment for depressive disorder in patients with depression.