Defined symptom-change trajectories during acute-phase cognitive therapy for depression predict better longitudinal outcomes

Background Acute-phase cognitive therapy (CT) is an efficacious treatment for major depressive disorder (MDD), but responders experience varying post-acute outcomes (e.g., relapse vs. recovery). Responders’ symptom-change trajectories during response to acute-phase CT may predict longer term outcomes. Method We studied adult outpatients (N = 220) with recurrent MDD who responded to CT but had residual symptoms. Responders with linear (steady improvement), log-linear (quicker improvement earlier and slower later), one-step (a single, relatively large, stable improvement between adjacent assessments), or undefined (not linear, log-linear, or one-step) symptom trajectories were assessed every 4 months for 32 additional months. Results Defined (linear, log-linear, one-step) versus undefined acute-phase trajectories predicted lower depressive symptoms (d = 0.36), lower weekly probability of being in a major depressive episode (OR = 0.46), higher weekly probabilities of remission (OR = 1.93) and recovery (OR = 2.35), less hopelessness (d = 0.41), fewer dysfunctional attitudes (d = 0.31), and better social adjustment (d = 0.32) for 32 months after acute-phase CT. Differences among defined trajectory groups were nonsignificant. Conclusions Responding to acute-phase CT with a defined trajectory (orderly pattern) of symptom reduction predicts better longer term outcomes, but which defined trajectory (linear, log-linear, or one-step) appears unimportant. Frequent measurement of depressive symptoms to identify un/defined CT response trajectories may clarify need for continued clinical monitoring and treatment.