title: Factors affecting recruitment into depression trials: Systematic review, meta-synthesis and conceptual framework.
abstract: BACKGROUND
  Depression is common and clinical trials are crucial for evaluating treatments. Difficulties in recruiting participants into depression trials are well-documented, yet no study has examined the factors affecting recruitment. This review aims to identify the factors affecting recruitment into depression trials and to develop a conceptual framework through systematic assessment of published qualitative research.
  
  
  METHODS
  Systematic review and meta-synthesis of published qualitative studies. Meta-synthesis involves a synthesis of themes across a number of qualitative studies to produce findings that are "greater than the sum of the parts". ASSIA, CINAHL, Embase, Medline and PsychInfo were searched up to April 2013. Reference lists of included studies, key publications and relevant reviews were also searched. Quality appraisal adopted the "prompts for appraising qualitative research".
  
  
  RESULTS
  7977 citations were identified, and 15 studies were included. Findings indicate that the decision to enter a depression trial is made by patients and gatekeepers based on the patient׳s health state at the time of being approached to participate; on their attitude towards the research and trial interventions; and on the extent to which patients become engaged with the trial. Our conceptual framework highlights that the decision to participate by both the patient and the gatekeeper involves a judgement between risk and reward.
  
  
  CONCLUSIONS
  Only English language publications were included in this review.
  
  
  CONCLUSIONS
  Findings from this review have implications for the design of interventions to improve recruitment into depression trials. Such interventions may aim to diminish the perceived risks and increase the perceived rewards of participation.
authors.affiliation: NIHR School for Primary Care Research, Manchester Academic Health Science Centre, Centre for Primary Care, Institute of Population Health, The University of Manchester, Manchester, UK. Electronic address: adwoa.hughes-morley@manchester.ac.uk.
authors.forename: Adwoa
authors.initials: A
authors.lastname: Hughes-Morley
authors.affiliation: MRC North West Hub for Trials Methodology Research, Institute of Psychology, Health and Society, University of Liverpool, Liverpool, UK.
authors.forename: Bridget
authors.initials: B
authors.lastname: Young
authors.affiliation: NIHR School for Primary Care Research, Manchester Academic Health Science Centre, Centre for Primary Care, Institute of Population Health, The University of Manchester, Manchester, UK.
authors.forename: Waquas
authors.initials: W
authors.lastname: Waheed
authors.affiliation: NIHR School for Primary Care Research, Manchester Academic Health Science Centre, Centre for Primary Care, Institute of Population Health, The University of Manchester, Manchester, UK.
authors.forename: Nicola
authors.initials: N
authors.lastname: Small
authors.affiliation: NIHR School for Primary Care Research, Manchester Academic Health Science Centre, Centre for Primary Care, Institute of Population Health, The University of Manchester, Manchester, UK.
authors.forename: Peter
authors.initials: P
authors.lastname: Bower
mesh_terms: D035061:Control Groups; D003866:Depressive Disorder / Q000628:therapy*; D006304:Health Status; D006801:Humans; D018579:Patient Selection; D036301:Qualitative Research
keywords: Conceptual framework; Depression; Meta-synthesis; Patient recruitment; Randomised controlled trials; Systematic review