In the United Kingdom, 1.24 million people suffer from depression annually. For a large proportion of these people, it is not the first time that they have a depressive episode. The relapse into depression is a major problem that occurs in 50 to 75% of people with previous depressive episodes. If depression returns it causes great suffering, loss of social roles, unproductiveness and high costs for society (estimated to be 7.5 billion pounds in the UK), in addition to risk of suicide and the risk of becoming a chronic depressive episode.
Read more (Department of Psychiatry website)