MDD is a chronic disorder, most frequently characterised by relapses and recurrences.2 Relapse can be defined as an episode of MDD that occurs within 6 months of response or remission;2,3 theoretically, relapse signifies the return of a major depressive episode, rather than a new episode.4,5 Recurrence can be defined as a depressive episode that occurs after 6 months following response or remission;2,3 theoretically, recurrence signifies the start of a new major depressive episode.4,5 Naturalistic studies have found that most patients will eventually experience either relapse or recurrence if followed for a long enough period without sustained treatment.2,6 Following an acute depressive episode, almost 90% of patients could be expected to become depressed again in the next 15 years.2,7
References:
1.Kupfer DJ. Long-term treatment of depression. J Clin Psychiatry 1991; 52 (Suppl 5): 28–34.
2.Nierenberg AA, Petersen TJ, Alpert JE. Prevention of relapse and recurrence in depression: the role of long-term pharmacotherapy and psychotherapy. J Clin Psychiatry 2003; 62 (Suppl 15): 13–17.
3.Riso LP, Thase ME, Howland RH, et al. A prospective test of criteria for response, remission, relapse, recovery, and recurrence in depressed patients treated with cognitive behavior therapy. J Affect Disord 1997; 43 (2): 131–142.
4.Nierenberg AA, DeCecco LM. Definitions of antidepressant treatment response, remission, nonresponse, partial response, and other relevant outcomes: a focus on treatment-resistant depression. J Clin Psychiatry 2001; 62 (Suppl 16): 5–9.
5.Frank E, Prien RF, Jarrett RB, et al. Conceptualization and rationale for consensus definitions of terms in major depressive disorder. Remission, recovery, relapse, and recurrence. Arch Gen Psychiatry 1991; 48 (9): 851–855.
6.Lavori PW, Keller MB, Mueller TI, et al. Recurrence after recovery in unipolar MDD: an observational follow-up study of clinical predictors and somatic treatment as a mediating factor. Int J Methods Psychiatr Res 1994; 4 (4): 211–229.
7.Keller MB. Long-term treatment of recurrent and chronic depression. J Clin Psychiatry 2001; 62 (Suppl 24): 3–5.
