title: Prevalence and characteristics of probable major depression and bipolar disorder within UK biobank: cross-sectional study of 172,751 participants.
abstract: OBJECTIVE
  UK Biobank is a landmark cohort of over 500,000 participants which will be used to investigate genetic and non-genetic risk factors for a wide range of adverse health outcomes. This is the first study to systematically assess the prevalence and validity of proposed criteria for probable mood disorders within the cohort (major depression and bipolar disorder).
  
  
  METHODS
  This was a descriptive epidemiological study of 172,751 individuals assessed for a lifetime history of mood disorder in relation to a range of demographic, social, lifestyle, personality and health-related factors. The main outcomes were prevalence of a probable lifetime (single) episode of major depression, probable recurrent major depressive disorder (moderate), probable recurrent major depressive disorder (severe), probable bipolar disorder and no history of mood disorder (comparison group). Outcomes were compared on age, gender, ethnicity, socioeconomic status, educational attainment, functioning, self-reported health status, current depressive symptoms, neuroticism score, smoking status and alcohol use.
  
  
  RESULTS
  Prevalence rates for probable single lifetime episode of major depression (6.4%), probable recurrent major depression (moderate) (12.2%), probable recurrent major depression (severe) (7.2%) and probable bipolar disorder (1.3%) were comparable to those found in other population studies. The proposed diagnostic criteria have promising validity, with a gradient in evidence from no mood disorder through major depression and probable bipolar disorder in terms of gender distribution, socioeconomic status, self-reported health rating, current depressive symptoms and smoking.
  
  
  CONCLUSIONS
  The validity of our proposed criteria for probable major depression and probable bipolar disorder within this cohort are supported by these cross-sectional analyses. Our findings are likely to prove useful as a framework for a wide range of future genetic and non-genetic studies.
authors.affiliation: Institute of Health and Wellbeing, Mental Health and Wellbeing Research Group, University of Glasgow, Glasgow, United Kingdom.
authors.forename: Daniel J
authors.initials: DJ
authors.lastname: Smith
authors.forename: Barbara I
authors.initials: BI
authors.lastname: Nicholl
authors.forename: Breda
authors.initials: B
authors.lastname: Cullen
authors.forename: Daniel
authors.initials: D
authors.lastname: Martin
authors.forename: Zia
authors.initials: Z
authors.lastname: Ul-Haq
authors.forename: Jonathan
authors.initials: J
authors.lastname: Evans
authors.forename: Jason M R
authors.initials: JM
authors.lastname: Gill
authors.forename: Beverly
authors.initials: B
authors.lastname: Roberts
authors.forename: John
authors.initials: J
authors.lastname: Gallacher
authors.forename: Daniel
authors.initials: D
authors.lastname: Mackay
authors.forename: Matthew
authors.initials: M
authors.lastname: Hotopf
authors.forename: Ian
authors.initials: I
authors.lastname: Deary
authors.forename: Nick
authors.initials: N
authors.lastname: Craddock
authors.forename: Jill P
authors.initials: JP
authors.lastname: Pell
mesh_terms: D000328:Adult; D000368:Aged; D001714:Bipolar Disorder / Q000175:diagnosis / Q000453:epidemiology / Q000235:genetics; D003430:Cross-Sectional Studies; D003865:Major Depressive Disorder / Q000175:diagnosis / Q000453:epidemiology* / Q000235:genetics; D005260:Female; D020022:Genetic Predisposition to Disease; D006801:Humans; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D011336:Probability; D012307:Risk Factors; D012959:Socioeconomic Factors; D006113:United Kingdom