[The duration of untreated depression is associated with a poor treatment response]

According to clinical lore the duration of untreated depression is associated with a poor treatment response. This is in accordance with the kindling hypothesis of depression. It is an important subject, since the duration of untreated depression is a potentially modifiable risk factor. Despite this, relatively few studies addressing the problem exist. While an association between the duration of untreated depression and treatment response generally is found, the uncontrolled and often retrospective nature of these studies makes it difficult to ascertain causality.