[Long-term treatment and prevention of depression]

Significant gains both for the individual patient and for the community can be made by preventing relapse and new depressive episodes. The depth of depression and the presence of other psychiatric problems are the most significant determinants of the duration of a depressive episode. The number of previous depressive episodes and age at first depression are the most significant determinants of the risk of future depression. However, the presence of interpersonal and social problems, other psychiatric or physical disorders, and the type of depression (e.g. depression as one "pole' in a bipolar disorder, dysthymia) are also factors of importance. The aim of maintenance treatment (i.e., continued treatment after the patient's recovery) is to prevent recurrence of the depressive episode, whereas the purpose of preventive treatment is to impede the occurrence of new depressive episodes.