Moving from Efficacy to Effectiveness in Depression Prevention Trials: A Dimensional Perspective

Prevention programs are essential for promoting health and reducing costs to individuals and society. Although many programs have been able to demonstrate efficacy under ideal conditions (e.g., carefully selected participants; highly qualified implementers of the intervention), these effects often diminish as we move toward more real-world delivery. Typically, this decline in effects is thought to result from factors related to sampling and broad program delivery (e.g., setting, practitioner). To our knowledge, however, little research exists quantifying the extent to which intervention effects diminish with the progression from efficacy to effectiveness, and identifying specific differences in study characteristics that may contribute to such declining effects. Examining the research cycle dimensionally from efficacy to effectiveness, allows us to evaluate the extent to which external and ecological validity moderate the effects of prevention programs on outcomes, and to identify which aspects of the program delivery (e.g., interventionist experience and qualifications) account for these effects.

This poster will present the results of a meta-analytic review of peer-reviewed, randomized controlled trials testing the effects of programs aimed at preventing depression in youth. A primary goal of this review is to evaluate the extent to which external validity characteristics predict the magnitude of study effect sizes. We developed a 15-item Likert scale to measure, dimensionally, where the study lies on the continuum from efficacy to effectiveness, with higher scores representing increasing levels of external and ecological validity. Preliminary findings from a mixed-effects meta-analysis of 40 studies, thus far, revealed that the magnitude of both post-intervention and 6-month follow-up effects on depressive symptoms (Hedges’ g) declined linearly as studies moved from tightly controlled designs with minimal external/ecological validity to studies with greater external/ecological validity (b = 0.04, 95% CI [0.01, 0.06]; b = 0.03, 95% CI [0.01, 0.05]). We will present findings from the full set of trials meeting the study inclusion criteria.

We anticipate that this information will help inform researchers about which characteristics contribute to a program’s effects and its ability to sustain these effects even under more realistic delivery. Additionally, the results of this study highlight the need for clarity in the literature regarding program delivery and design in order to improve replication of studies and to facilitate a more uniform evaluation across RCTs of what factors are associated with enduring effects.