Sudden gains have been shown to be a common phenomenon and an important predictor of outcome in psychotherapy (Tang & DeRubeis, 1999). The present meta-analysis examined the growing literature on sudden gains in psychotherapy, their effects on outcome, and moderators of these effects. We searched PsycINFO, PubMed, ProQuest Dissertations & Theses, Scholar and Web of Science databases for articles between January 1st 1999 and May 31st 2019 and included 50 studies (n = 6355) in the meta-analysis. Sudden gains were found to significantly predict outcome at post-treatment (g = 0.68) and follow up (g = 0.61) above and beyond treatments, disorders and settings. Studies using Tang and DeRubies's (1999) criteria for identification of sudden gains had smaller effect sizes compared to studies using altered criteria. Pretreatment severity levels did not significantly predict the effects of sudden gains and neither did treatment setting (randomized controlled trials vs. naturalistic settings). Finally, number of sessions and sudden gains' reversal rates were both negatively associated with the effect sizes of sudden gains. These findings suggest that sudden gains are a ubiquitous phenomenon in psychotherapy but their effects may be moderated by a number of factors. Research and clinical implications are discussed.

突如其来的收获已被证明是一种普遍现象，并且是心理治疗结果的重要预测指标（Tang＆DeRubeis，1999）。本荟萃分析研究了关于心理治疗突然获益，其对预后的影响以及这些作用的调节因素的文献。我们检索PsycINFO，考研，ProQuest的论文及论文，学者和1999年1月1日和2019年5月31日之间的文章科学数据库的网站，其中包括50个研究（ñ = 6355）。发现突然增加的收益可显着预测治疗后（g = 0.68）的结果，以及在治疗，失调和背景之外的随访情况（g = 0.61）。与使用变更标准的研究相比，使用Tang和DeRubies（1999）的标准进行突然收益识别的研究具有较小的效应量。治疗前的严重程度水平不能显着预测突然发作的效果，治疗环境也不能（随机对照试验与自然环境对照）。最后，会议次数和突然收获的逆转率均与突然收获的效应大小负相关。这些发现表明，突然的收获是心理治疗中普遍存在的现象，但其影响可能受多种因素影响。