title: Does reverse causality explain the relationship between diet and depression?
abstract: BACKGROUND
  Observational studies have repeatedly demonstrated relationships between habitual diet quality and depression. However, whilst reverse causality has not been the identified mechanism for these associations in prospective studies, the relationship between diet and depression is likely complex and bidirectional. Thus explicit investigation of the reverse causality hypothesis is warranted.
  
  
  METHODS
  Data were drawn from the Personality and Total Health (PATH) Through Life Study, a longitudinal community survey following three age cohorts from Australia. Analyses evaluated the relationships between past depression and treatment, current depressive symptoms and dietary patterns.
  
  
  RESULTS
  Individuals with current depression had lower scores on a healthy dietary pattern; however, those who had been previously depressed and sought treatment had higher scores on the healthy dietary pattern at the later baseline assessment. Moreover, those who had reported prior, but not current, depression also had lower scores on the western dietary pattern than those without prior depression, regardless of whether they had been previously treated for their symptoms.
  
  
  CONCLUSIONS
  Self-report data and possible recall bias limit our conclusions.
  
  
  CONCLUSIONS
  In this study, prior depression was associated with better quality diets at the later time point. Thus, while current depression is associated with poorer dietary habits, a history of depression may prompt healthier dietary behaviours in the long term. Given the demonstrated relationships between diet quality and depressive illness, clinicians should advocate dietary improvement for their patients with depression and should not be pessimistic about the likelihood of adherence to such recommendations.
authors: IMPACT Strategic Research Centre, Deakin University, Geelong, Australia; Centre for Adolescent Health, Murdoch Children׳s Research Institute, Melbourne, Australia; Department of Psychiatry, The University of Melbourne, Melbourne, Australia; Black Dog Institute, Sydney, Australia. Electronic address: f.jacka@deakin.edu.au.
authors: Felice N
authors: FN
authors: Jacka
authors: Centre for Research on Ageing, Health & Well-being, The Australian National University, Canberra, Australia.
authors: Nicolas
authors: N
authors: Cherbuin
authors: Centre for Research on Ageing, Health & Well-being, The Australian National University, Canberra, Australia.
authors: Kaarin J
authors: KJ
authors: Anstey
authors: Centre for Research on Ageing, Health & Well-being, The Australian National University, Canberra, Australia.
authors: Peter
authors: P
authors: Butterworth
mesh_terms: D000328:Adult; D001315:Australia; D003430:Cross-Sectional Studies; D003863:Depression / Q000523:psychology*; D005247:Feeding Behavior / Q000523:psychology*; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies
keywords: Causality; Depression; Diet; Prevention