title: Unrecognised bipolar disorder in primary care patients with depression.
abstract: BACKGROUND
  Bipolar disorder is complex and can be difficult to diagnose. It is often misdiagnosed as recurrent major depressive disorder.
  
  
  OBJECTIVE
  We had three main aims. To estimate the proportion of primary care patients with a working diagnosis of unipolar depression who satisfy DSM-IV criteria for bipolar disorder. To test two screening instruments for bipolar disorder (the Hypomania Checklist (HCL-32) and Bipolar Spectrum Diagnostic Scale (BSDS)) within a primary care sample. To assess whether individuals with major depressive disorder with subthreshold manic symptoms differ from those individuals with major depressive disorder but with no or little history of manic symptoms in terms of clinical course, psychosocial functioning and quality of life.
  
  
  METHODS
  Two-phase screening study in primary care.
  
  
  RESULTS
  Three estimates of the prevalence of undiagnosed bipolar disorder were obtained: 21.6%, 9.6% and 3.3%. The HCL-32 and BSDS questionnaires had quite low positive predictive values (50.0 and 30.1% respectively). Participants with major depressive disorder and with a history of subthreshold manic symptoms differed from those participants with no or little history of manic symptoms on several clinical features and on measures of both psychosocial functioning and quality of life.
  
  
  CONCLUSIONS
  Between 3.3 and 21.6% of primary care patients with unipolar depression may have an undiagnosed bipolar disorder. The HCL-32 and BSDS screening questionnaires may be more useful for detecting broader definitions of bipolar disorder than DSM-IV-defined bipolar disorder. Subdiagnostic features of bipolar disorder are relatively common in primary care patients with unipolar depression and are associated with a more morbid course of illness. Future classifications of recurrent depression should include dimensional measures of bipolar symptoms.
authors.affiliation: Department of Psychological Medicine and Neurology, Cardiff University School of Medicine, University Hospital of Wales, Cardiff, UK. smithdj3@cardiff.ac.uk
authors.forename: Daniel J
authors.initials: DJ
authors.lastname: Smith
authors.forename: Emily
authors.initials: E
authors.lastname: Griffiths
authors.forename: Mark
authors.initials: M
authors.lastname: Kelly
authors.forename: Kerry
authors.initials: K
authors.lastname: Hood
authors.forename: Nick
authors.initials: N
authors.lastname: Craddock
authors.forename: Sharon A
authors.initials: SA
authors.lastname: Simpson
mesh_terms: D000328:Adult; D001714:Bipolar Disorder / Q000175:diagnosis / Q000453:epidemiology* / Q000523:psychology; D003866:Depressive Disorder / Q000175:diagnosis / Q000453:epidemiology* / Q000523:psychology; D003937:Diagnosis, Differential; D039721:Diagnostic and Statistical Manual of Mental Disorders; D005188:False Negative Reactions; D005194:Family Practice; D005260:Female; D006801:Humans; D008297:Male; D008403:Mass Screening; D015995:Prevalence; D011320:Primary Health Care / Q000706:statistics & numerical data*; D011569:Psychiatric Status Rating Scales / Q000592:standards; D011788:Quality of Life; D012372:ROC Curve; D006113:United Kingdom / Q000453:epidemiology