In reply: Fava observes that duration of treatment with an antidepressant does not affect the subsequent rate of relapse. Indeed, it would be unexpected if it did; medication only works while it is being taken. He then states that the duration of antidepressant treatment is immaterial. However, Figure 1 of the reference he quotes1 indicates that, for at least 54 months after the index episode, continuing medication provides greater protection against relapse than early discontinuation.

This argues strongly for the beneficial effects of continuing antidepressant therapy for a significant period after recovery. The duration of this period depends on the number of previous episodes of depression and is a compromise between the benefits of effective prophylaxis and the burden of treatment.

He also refers to a study of "tolerance" to 20 mg fluoxetine.2 Of patients who responded to treatment, 31.4% relapsed while on maintenance treatment. Of these, 57% responded to an increase to 40 mg fluoxetine and remained well for six months. He appears to have interpreted these data differently.

I agree that treating depression involves more than prescribing. The beyondblue guidelines promote active collaboration with the depressed person in addressing key issues in their lives and a focus on relapse prevention.3 Cognitive behavioural therapy is one strategy for achieving this.