How long should drug treatment of depression last?

To the Editor: The beyondblue guidelines for treating depression in primary care by Ellis and Smith1 are intended to assist both healthcare professionals and consumers. While they provide several helpful indications, they also include some misleading suggestions. The authors state that drug treatment of depression should continue for at least one year for a first episode of depression, and at least two years for repeated episodes or when there are other risk factors for relapse. However, no background literature is cited in support of this statement, and indeed would be difficult to find.

Maintenance pharmacotherapy has been advocated as an effective tool for reducing relapses and recurrences in major depression.2 A number of studies have shown the superiority of antidepressant drugs (mostly tricyclics) compared with placebo in protecting the patient from relapse. Duration of drug treatment, however, did not seem to affect long-term prognosis once treatment with the drug was discontinued. In clinical terms this means that, whether you treat a depressed patient for three months or three years, it does not matter when you stop therapy with the drug. In fact, after recovery from an index episode of major depression, risk of postdiscontinuation relapse was nearly significantly greater after longer treatment (ρ = 0.37; P = 0.052).3

Further, Ellis and Smith1 fail to mention a vexing clinical problem in maintenance antidepressant treatment: the return of depressive symptoms.3 Dose increase is likely to entail only a temporary solution to the problem, which may occur in up to 57% of patients.

However, there is a promising alternative. Treatment of depression by pharmacological means is likely to leave substantial residual symptoms.4 Residual symptoms hinder lasting recovery and are one of the strongest risk factors for relapse. In randomised controlled trials, cognitive behavioural treatment of residual symptoms was found to significantly improve long-term outcome of recurrent depression and to allow discontinuation of drug therapy.4

Preventing recurrence in major depression cannot simply be based on prolonging ongoing pharmacological treatment. The belief that a longer course of treatment will result in a more favourable outcome after discontinuation of antidepressant drug therapy is not supported by research evidence.5 Active collaboration with the patient (in choosing a treatment option, in lifestyle modification, in seeking treatment again when needed) is a crucial, and yet neglected, variable. It can lead to a more rational use of antidepressant drugs and to therapeutic efforts of more enduring quality than those prevailing today.