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 remain unclear. AIM: The current 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 were conducted, including studies found in Medline, PsychINFO, SCOPUS, Web of Science, and through reference lists and reverse citations.
RESULTS: Twenty-five eligible studies including 11,091 patients measured early response and examined associations with posttreatment 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% confidence interval: 0.63-1.10], p < .0001) indicated that early responders had significantly better posttreatment 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 precluded their inclusion in meta-analysis, and it was not possible to examine effect sizes according to different outcome questionnaires.
CONCLUSION: There is robust and replicated evidence that early response to therapy is a reliable prognostic indicator for depression and anxiety treatment outcomes.