title: Sudden gains during psychological treatments of anxiety and depression: a meta-analysis.
abstract: OBJECTIVE
  The present study quantitatively reviewed the literature on sudden gains in psychological treatments for anxiety and depression. The authors examined the short- and long-term effects of sudden gains on treatment outcome as well as moderators of these effects.
  
  
  METHODS
  The authors conducted a literature search using PubMed, PsycINFO, the Cochrane Library, and manual searches. The meta-analysis was based on 16 studies and included 1,104 participants receiving psychological treatment for major depressive disorder or an anxiety disorder.
  
  
  RESULTS
  Effect size estimates suggest that sudden gains had a moderate effect on primary outcome measures at posttreatment (Hedges's g = 0.62) and follow-up (Hedges's g = 0.56). These effect sizes were robust and unrelated to publication year or number of treatment sessions. The effect size of sudden gains in cognitive-behavioral therapy was higher (Hedges's g = 0.75) than in other treatments (Hedges's g = 0.23).
  
  
  CONCLUSIONS
  These results suggest that sudden gains are associated with short-term and long-term improvements in depression and anxiety, especially in cognitive-behavioral therapy.
authors: Department of Psychology, Boston University, 648 Beacon Street, Boston, MA 02215, USA. iaderka@bu.edu
authors: Idan M
authors: IM
authors: Aderka
authors: Angela
authors: A
authors: Nickerson
authors: Hans Jakob
authors: HJ
authors: Bøe
authors: Stefan G
authors: SG
authors: Hofmann
mesh_terms: D001008:Anxiety Disorders / Q000628:therapy*; D015928:Cognitive Behavioral Therapy / Q000379:methods*; D003865:Major Depressive Disorder / Q000628:therapy*; D005500:Follow-Up Studies; D006801:Humans; D016896:Treatment Outcome