title: Impact of functional and structural social relationships on two year depression outcomes: A multivariate analysis.
abstract: BACKGROUND
  High rates of persistent depression highlight the need to identify the risk factors associated with poor depression outcomes and to provide targeted interventions to people at high risk. Although social relationships have been implicated in depression course, interventions targeting social relationships have been disappointing. Possibly, interventions have targeted the wrong elements of relationships. Alternatively, the statistical association between relationships and depression course is not causal, but due to shared variance with other factors. We investigated whether elements of social relationships predict major depressive episode (MDE) when multiple relevant variables are considered.
  
  
  METHODS
  Data is from a longitudinal study of primary care patients with depressive symptoms. 494 participants completed questionnaires at baseline and a depression measure (PHQ-9) two years later. Baseline measures included functional (i.e. quality) and structural (i.e. quantity) social relationships, depression, neuroticism, chronic illness, alcohol abuse, childhood abuse, partner violence and sociodemographic characteristics. Logistic regression with generalised estimating equations was used to estimate the association between social relationships and MDE.
  
  
  RESULTS
  Both functional and structural social relationships predicted MDE in univariate analysis. Only functional social relationships remained significant in multivariate analysis (OR: 0.87; 95%CI: 0.79-0.97; p=0.01). Other unique predictors of MDE were baseline depression severity, neuroticism, childhood sexual abuse and intimate partner violence.
  
  
  CONCLUSIONS
  We did not assess how a person's position in their depression trajectory influenced the association between social relationships and depression.
  
  
  CONCLUSIONS
  Interventions targeting relationship quality may be part of a personalised treatment plan for people at high risk due of persistent depression due to poor social relationships.
authors.affiliation: Department of General Practice Faculty of Medicine, Dentistry & Health Sciences University of Melbourne, Australia. Electronic address: sdav@unimelb.edu.au.
authors.forename: Sandra K
authors.initials: SK
authors.lastname: Davidson
authors.affiliation: Institute of Psychology Health and Society University of Liverpool, United Kingdom.
authors.forename: Christopher F
authors.initials: CF
authors.lastname: Dowrick
authors.affiliation: Department of General Practice Faculty of Medicine, Dentistry & Health Sciences University of Melbourne, Australia.
authors.forename: Jane M
authors.initials: JM
authors.lastname: Gunn
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D003865:Major Depressive Disorder / Q000175:diagnosis* / Q000523:psychology*; D005260:Female; D006801:Humans; D007398:Interpersonal Relations; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D012307:Risk Factors; D011795:Surveys and Questionnaires; D055815:Young Adult
keywords: Depression; Primary care; Prospective; Social relationships