Quantifying and qualifying the preventive effects of acute-phase cognitive therapy: Pathways to personalizing care

Abstract

Objective: To determine the extent to which prospectively identified responders to cognitive therapy (CT) for recurrent major depressive disorder (MDD) hypothesized to be lower risk show significantly less relapse or recurrence than treated higher risk counterparts across 32 months.

Method: Outpatients (N = 523), aged 18-70, with recurrent MDD received 12-14 weeks of CT. The last 7 consecutive scores from the Hamilton Rating Scale for Depression (HRSD-17) were used to stratify or define responders (n = 290) into lower (7 HRSD-17 scores of less than or equal to 6; n = 49; 17%) and higher risk (n = 241; 83%). The lower risk patients entered the 32-month follow-up. Higher risk patients were randomized to 8 months of continuation-phase CT or clinical management plus double-blind fluoxetine or pill placebo, with a 24-month follow-up.

Results: Lower risk patients were significantly less likely to relapse over the first 8 months compared to higher risk patients (Kaplan-Meier [KM] estimates; i.e., 4.9% = lower risk; 22.1% = higher risk; log-rank χ2 = 6.83, p = .009). This increased risk was attenuated, but not completely neutralized, by active continuation-phase therapy. Over the subsequent 24 months, the lower and higher risk groups did not differ in relapse or recurrence risk.

Conclusions: Rapid and sustained acute-phase CT remission identifies responders who do not require continuation-phase treatment to prevent relapse (i.e., return of an index episode). To prevent recurrence (i.e., new episodes), however, strategic allocation and more frequent "dosing" of CT and/or targeted maintenance-phase treatments may be required. Longitudinal follow-up is recommended.

Figure 1

The Consort 2010 Flow Diagram For Division by Strata

Figure 2

Kaplan-Meier time-to-event curves for relapse or recurrence (DSM-IV major depressive disorder) diagnosed by a blind evaluator over 32 months (139 weeks) in lower and higher risk strata. Log-rank tests showed significant differences between risk strata through 8 months, χ²(1) = 6.83, p < .01, but not 20 months, χ²(1) = 2.89, p = .09, or 32 months, χ²(1) = 3.00, p = .08.