title: The influence of anxiety as a risk to early onset major depression.
abstract: OBJECTIVE
  we seek to identify and quantify any risk provided by several expressions of "anxiety" to major depression overall, and to separate melancholic and non-melancholic sub-types.
  
  
  METHODS
  a sample of 269 patients with a current major depressive episode was assessed for rates of separate formalised anxiety disorders, both for lifetime and prior to the initial depressive episode. We also sought for evidence of familial anxiety and, early childhood expression of anxiety forerunners, measured both state and trait anxiety levels as well as anxiety at a "personality" level, and assessed use of anxiolytic medications. Depressive sub-typing was undertaken using DSM-IV criteria, while "early onset" (EO) depression was defined as an initial onset at 25 years or less, and subsequently re-examined with a cut-off age of 20 years or less.
  
  
  RESULTS
  overall. 42% of our sample were assigned as having EO depression, with there being a higher representation of non-melancholic than melancholic EO subjects (i.e., 51% vs. 29%), arguing for sub-type status being respected in the analyses. For both melancholic and non-melancholic subjects two trait anxiety items ("tense"; "keyed up/on edge") were over-represented, suggesting that such a tense anxiety style may provide an antecedent risk to depression (of either sub-type) or be a consequence of depression. Specificity was most evident in the non-melancholic sub-sample, where EO depression was associated with a family history of anxiety, early childhood expressions of anxiety and with two lifetime anxiety disorders (social phobia and obsessive-compulsive disorder). Broadly similar results were returned when "EO" definition was reduced to 20 years or less.
  
  
  CONCLUSIONS
  our study is consistent with previous research in identifying anxiety in the form of social inhibition or social avoidance as being particularly likely to precede and perhaps be a conduit to early onset non-melancholic major depression. This conclusion both sharpens risk factor research and indicates an important fulcrum that could be used to assist primary prevention of the depressive disorders.
authors.affiliation: Psychiatry Unit, The Prince of Wales Hospital, Randwick, New South Wales, Australia.
authors.forename: G
authors.initials: G
authors.lastname: Parker
authors.forename: K
authors.initials: K
authors.lastname: Wilhelm
authors.forename: P
authors.initials: P
authors.lastname: Mitchell
authors.forename: M P
authors.initials: MP
authors.lastname: Austin
authors.forename: J
authors.initials: J
authors.lastname: Roussos
authors.forename: G
authors.initials: G
authors.lastname: Gladstone
mesh_terms: D000328:Adult; D000367:Age Factors; D001008:Anxiety Disorders / Q000175:diagnosis* / Q000523:psychology*; D003865:Major Depressive Disorder / Q000175:diagnosis* / Q000209:etiology*; D005260:Female; D006801:Humans; D008297:Male; D010552:Personality Assessment; D011569:Psychiatric Status Rating Scales; D012720:Severity of Illness Index