The course of MDD

This image illustrates course of major depressive disorder (MDD).¹ The optimal outcome for a patient with MDD is a full recovery from the major depressive episode and to never become depressed again.⁵ Treatment of MDD is divided into three phases, corresponding to different stages of the illness.⁶ Each of these phases has a different treatment goal.⁶

Acute treatment phase

‘Acute phase treatment’ of MDD occurs during a major depressive episode; it runs from the initiation of treatment until remission is achieved.^1,3 The goals of acute phase treatment are to achieve remission (removal of symptoms, such that the criteria for a major depressive episode are no longer met), and an improvement in functioning and quality of life.^2,3 Remission is a clinically-meaningful endpoint: patients who achieve remission are less likely to relapse than those who do not achieve remission.^7,8 Response, i.e., a 50% improvement from baseline in a depression rating scale score, is an intermediate treatment goal; it is used to evaluate whether or not a treatment is benefiting the patient.³

Continuation treatment phase

‘Continuation phase treatment’ of MDD follows on from acute phase treatment, i.e., it starts when remission is achieved.^1,3 The goals of continuation phase treatment are to prevent a relapse (a return of symptoms sufficient to meet the criteria for a major depressive episode) in the vulnerable period immediately following remission, to eliminate any unresolved symptoms, and to restore the patient’s level of psychosocial and occupational functioning – at least to levels seen prior to the current episode and, if possible, to levels seen prior to the onset of MDD.^2,3 Continuation phase treatment continues until recovery is achieved (the end of a major depressive episode).³ The moment of recovery is difficult to identify in clinical practice.³

Maintenance treatment phase

‘Maintenance phase treatment’ of MDD follows on from continuation phase treatment, provided the patient did not experience a relapse.^1,3 The goals of maintenance phase treatment are to prevent a new episode of depression (recurrence), to prevent suicide, and to enable full and lasting functional recovery.³ Typically, maintenance treatment is indicated in patients with chronic/recurrent MDD (i.e., those susceptible to recurrence).²

Note: There is a lack of empirical evidence to differentiate between relapse and recurrence, hence, the continuation and maintenance phases are often combined into a single maintenance phase⁴

MDD=major depressive disorder