title: Behavior change through automated e-mails: mediation analysis of self-help strategy use for depressive symptoms.
abstract: OBJECTIVE
  To evaluate whether automated e-mails promoting effective self-help strategies for depressive symptoms were effective in changing self-help behavior, and whether this improved depression outcomes.
  
  
  METHODS
  568 adults with sub-threshold depression participated in a randomized controlled trial and provided complete data. A series of 12 e-mails promoting the use of evidence-based self-help strategies was compared with e-mails providing non-directive depression information. Depression symptoms were assessed with the Patient Health Questionnaire depression scale (PHQ-9) and use of self-help strategies was assessed at baseline and post-intervention. We hypothesized that those receiving the self-help e-mails would increase their use of evidence-based self-help and this would be associated with improvements in depression. Mediation analyses were conducted using a non-parametric bootstrapping procedure.
  
  
  RESULTS
  Total use of the self-help strategies promoted in the e-mails significantly mediated the effect of the intervention on depressive symptoms (B = -0.75, SE = 0.16, 95% CI: -1.06 to -0.48). The direct effect of the intervention on depressive symptoms was much smaller and not significant when the mediation path was included. The majority of the individual strategies also had a significant indirect effect on depressive symptoms.
  
  
  CONCLUSIONS
  In adults with sub-threshold depression, automated e-mails based on behavior change principles can successfully increase use of self-help strategies, leading to a reduction in depressive symptoms.
authors.affiliation: Orygen Youth Health Research Centre, Centre for Youth Mental Health, The University of Melbourne, Parkville, Victoria, Australia. ajmorgan@unimelb.edu.au
authors.forename: Amy J
authors.initials: AJ
authors.lastname: Morgan
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Mackinnon
authors.forename: Anthony F
authors.initials: AF
authors.lastname: Jorm
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001521:Behavior Therapy / Q000379:methods*; D003863:Depression / Q000628:therapy*; D034742:Electronic Mail / Q000706:statistics & numerical data*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D017008:Negotiating; D012648:Self Care / Q000706:statistics & numerical data*; D016896:Treatment Outcome; D055815:Young Adult