Early response to psychological therapy as a predictor of depression and anxiety treatment outcomes: A systematic review and meta-analysis

Background: Previous studies indicate that early symptomatic improvement, typically observed during the first 4 weeks of psychological therapy, is associated with positive treatment outcomes for a range of mental health problems. However, the replicability, statistical significance and magnitude of this association remains unclear.

Aim: The present study reviewed the literature on early response to psychological interventions for adults with depression and anxiety symptoms.

Methods: A systematic review and random effects meta-analysis was conducted, including studies found in Medline, PsychINFO, SCOPUS, Web of Science, and through reference lists and reverse citations.

Results: Twenty-five eligible studies including 11091 patients measured early response and examined associations with post-treatment outcomes. It was possible to extract and/or calculate effect size data from 15 studies to conduct a meta-analysis. A large pooled effect size (g = 0.87 [95 % CI: 0.63, 1.10] p < .0001) indicated that early responders had significantly better post-treatment outcomes compared to cases without early response, and this effect was larger in anxiety (g = 1.37) compared to depression (g = 0.76) measures. Most studies were of good quality and there was no evidence of publication bias. The main limitations concerned insufficient statistical reporting in some studies, which meant that the meta-analysis only included 60% of reviewed studies, and it was not possible to examine effect sizes according to different outcome questionnaires.

Conclusions: There is robust and replicated evidence that early response to therapy is a reliable prognostic indicator for depression and anxiety treatment outcomes.