Longer-term outcome in depression

With modern treatment, the immediate outcome of episodes of depression is relatively good. Follow-up studies show that most patients improve considerably within a few months of presentation, although in a proportion remission is delayed or there are residual symptoms and a small number of patients remain severely ill and treatment resistant. It takes some years before longer term outcome can be evaluated after introduction of therapeutic advances. The antidepressants came into use just before the beginning of the 1960s, and for some time it was the good short term outcome that was most apparent. However in recent years it has become apparent that the longer-term outcome beyond immediate remission is far less satisfactory.

Relapse or recurrence?

It has become customary in the literature to distinguish between early and late symptom return (Frank et al., 1991). The term relapse is used for an early return of symptoms, within the first six to nine months. This can plausibly be seen as return of the original episode in which the symptoms have been suppressed by treatment, but the underlying biological process may not have recovered. The term recurrence is used to describe later symptom return which it is assumed represents occurrence of a new episode. The distinction, although useful, is not hard and fast.