title: Systematic review and meta-analysis of group cognitive behavioural psychotherapy treatment for sub-clinical depression.
abstract: BACKGROUND
  Studies investigating effectiveness of group psychotherapy intervention in sub-threshold depression have shown varying results with differing effect sizes.
  
  
  OBJECTIVE
  A systematic review of randomised controlled trials of group psychotherapy in adults with sub-threshold depression has been conducted to present the best available evidence in relation to its effect on depressive symptomatology and prevention of incident major depression.
  
  
  METHODS
  Electronic search for RCTs and a meta-analysis using random effects models to obtain a pooled estimate.
  
  
  RESULTS
  Eight studies from six clinical trials met the inclusion criteria. Group psychotherapy is an effective intervention for reducing depressive symptoms in adults with sub-threshold depression in comparison to waiting list controls (MD=-3.48, 95% CI: -5.02, -1.93). The reported benefits for group intervention in reducing depressive symptoms in comparison to other active interventions did not reach statistical significance (MD=0.37 95% CI: -1.29, 2.04). The benefit of group psychotherapy at follow-up is not maintained. Group psychotherapies do not appear to reduce the risk of incident depressive disorder during the follow up (RR=1.15 95% CI: 0.85, 1.54). Dutch studies had bigger effect sizes than studies from other countries. The quality of reporting of all the studies was suboptimal.
  
  
  CONCLUSIONS
  The results of this meta-analysis show that group CBT interventions for patients with sub-threshold depression have a significant effect on depressive symptomatology at post treatment in both working age and older adult population. However it does not appear to reduce the incidence of major depressive disorders and has minimal or no effect on depressive symptomatology during follow-up.
authors.affiliation: Early Career Research Fellow, Wellcome DBT Alliance and Consultant Psychiatrist, CSI Holdsworth Memorial Hospital, Mysore, India. Electronic address: muralidoc@gmail.com.
authors.forename: Murali
authors.initials: M
authors.lastname: Krishna
authors.affiliation: Consultant Psychiatrist, BCUHB, North Wales, UK; Visiting Professor in Psychiatry at Bangor University, North Wales, UK. Electronic address: peter.lepping@wales.nhs.uk.
authors.forename: Peter
authors.initials: P
authors.lastname: Lepping
authors.affiliation: Senior Lecturer, Faculty of Health and Social Care, University of Edgehill, Omskirk, Lancashire, UK. Electronic address: joness@edgehill.ac.uk.
authors.forename: Steven
authors.initials: S
authors.lastname: Jones
authors.affiliation: Lecturer, Centre for Medical Statistics and Health Evaluation, Shelley's Cottage, University of Liverpool, Brownlow Street, Liverpool, L69 3GS, UK. Electronic address: slane@liv.ac.uk.
authors.forename: Steven
authors.initials: S
authors.lastname: Lane
mesh_terms: D000328:Adult; D015928:Cognitive Behavioral Therapy / Q000706:statistics & numerical data*; D003863:Depression / Q000628:therapy*; D003865:Major Depressive Disorder / Q000517:prevention & control*; D006801:Humans; D008875:Middle Aged; D017063:Outcome Assessment, Health Care / Q000706:statistics & numerical data*; D011615:Psychotherapy, Group / Q000706:statistics & numerical data*
keywords: CBT; Group psychotherapy; Meta-analysis; Sub-clinical depression; Systematic review