Changes in antidepressant therapy should be considered early in patients with inadequate response to a first-line agent.

Deciding when and how to change treatment in patients with major depressive disorder who have inadequate response to initial antidepressant therapy is an important everyday clinical question. Here, we ask whether an early change of approach is superior to a delayed change. We consider the recommendations provided by recent guidelines, examine the evidence behind this guidance and suggest a decision tree to clarify treatment options and timing. Both the early and late-change strategies may have their place in clinical practice. However, we take the view that an earlier than currently usual change in antidepressant treatment should be considered more frequently in cases of non-response. Specific studies are needed to identify and to better understand predictors of early and late response.