Stable remission and recovery after acute-phase cognitive therapy for recurrent major depressive disorder

Abstract

Objective: Continuation-phase cognitive therapy (C-CT) or fluoxetine (FLX) reduces relapse in adults with major depressive disorder (MDD; Jarrett, Minhajuddin, Gershenfeld, Friedman, & Thase, 2013). Among patients at higher risk for relapse, we hypothesized that continuation-phase treatment reduces residual symptoms and facilitates stable remission and recovery.

Method: Outpatients (N = 241) with recurrent MDD who responded to acute-phase CT with higher risk for relapse (i.e., had unstable remission defined by any of the last 7 acute-phase scores ≥ 7 using the Hamilton Rating Scale for Depression; Hamilton, 1960) were randomized to 8 months of C-CT, FLX, or pill placebo and followed for 24 additional months. Psychiatric status ratings (Keller et al., 1987) of 1 or 2 (absent or minimal depressive symptoms) for 6 and 35 continuous weeks post-randomization defined stable remission and recovery, respectively.

Results: Actuarial estimates of stable remission (97%) and recovery (94%) by the end of follow-up were high and did not differ among groups. Observed (unadjusted) proportions of patients remitting (70%) and recovering (47%) before relapse or attrition were lower. During the continuation phase, C-CT (d = 0.21) and FLX (d = 0.25) patients had significantly lower mean depressive symptoms than did controls, but C-CT and FLX patients did not differ from each other, nor did the 3 experimental groups differ during follow-up.

Conclusion: Many patients who responded to CT with higher relapse risk subsequently remitted and recovered after discontinuation of acute-phase treatment. After discontinuation, C-CT and FLX decreased levels of residual depressive symptoms, but neither significantly increased the likelihood of stable remission or recovery, beyond the moderate to high levels observed among patients who did not relapse.

Figure 1

The numbers inside the boxes reflect the number of patients who experienced each event. Arrows show the progression events within 32 months after discontinuation of A-CT.

Figure 2

Estimated probabilities of stable remission (6 weeks of consistently minimal or absent depressive symptoms) were derived from Cox regression analyses. The continuation phase cognitive therapy and pill placebo lines are nearly fully overlapping. Patients were censored before stable remission when they relapsed (and were referred for non-protocol treatment) or dropped out. Through the end of follow-up, the three groups did not differ in time to stable remission, χ²(2) = 0.95, p = .62.

Figure 3

Estimated probabilities of recovery (8 months of consistently minimal or absent depressive symptoms) were derived from Cox regression analyses. Patients were censored before recovery when they relapsed (and were referred for non-protocol treatment) or dropped out. Through the end of follow-up, the three groups did not differ in time to recovery, χ²(2) = 3.99, p = .14.

Figure 4

Estimated means were derived from a repeated-measures multilevel model controlling non-protocol treatment. Weekly mean Psychiatric Status Ratings are in the range of 1 (no depressive symptoms), 2 (one or two mild symptoms), and 3 (obvious symptoms with moderate impairment but does not meet criteria for major depressive disorder).