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

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.

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.

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.

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.