title: Definitions and factors associated with subthreshold depressive conditions: a systematic review.
abstract: BACKGROUND
  Subthreshold depressive disorders (minor and subthrehold depression) have been defined in a wide range of forms, varying on the number of symptoms and duration required. Disability associated with these conditions has also been reported. Our aim was to review the different definitions and to determine factors associated with these conditions in order to clarify the nosological implications of these disorders.
  
  
  METHODS
  A Medline search was conducted of the published literature between January 2001 and September 2011. Bibliographies of the retrieved papers were also analysed.
  
  
  RESULTS
  There is a wide heterogeneity in the definition and diagnostic criteria of minor and subthreshold depression. Minor depression was defined according to DSM-IV criteria. Regarding subthreshold depression, also called subclinical depression or subsyndromal symptomatic depression, between 2 and 5 depressive symptoms were required for the diagnosis, and a minimum duration of 2 weeks. Significant impairment associated with subthreshold depressive conditions, as well as comorbidity with other mental disorders, has been described.
  
  
  CONCLUSIONS
  Depression as a disorder is better explained as a spectrum rather than as a collection of discrete categories. Minor and subthreshold depression are common conditions and patients falling below the diagnostic threshold experience significant difficulties in functioning and a negative impact on their quality of life. Current diagnostic systems need to reexamine the thresholds for depressive disorders and distinguish them from ordinary feelings of sadness.
authors.affiliation: Instituto de Salud Carlos III, Centro de Investigación Biomédica en Red de Salud Mental, CIBERSAM, Madrid, Spain.
authors.forename: Mar Rivas
authors.initials: MR
authors.lastname: Rodríguez
authors.forename: Roberto
authors.initials: R
authors.lastname: Nuevo
authors.forename: Somnath
authors.initials: S
authors.lastname: Chatterji
authors.forename: José Luis
authors.initials: JL
authors.lastname: Ayuso-Mateos
mesh_terms: D003866:Depressive Disorder / Q000145:classification / Q000175:diagnosis* / Q000453:epidemiology / Q000628:therapy; D003937:Diagnosis, Differential; D039721:Diagnostic and Statistical Manual of Mental Disorders; D006801:Humans; D015995:Prevalence