title: Prevalence of treatment-resistant depression in primary care: cross-sectional data.
abstract: BACKGROUND
  Antidepressants are often the first-line treatment for depression in primary care. However, not all patients respond to medication after an adequate dose and duration of treatment. Currently, there are no estimates of the prevalence of treatment-resistant depression (TRD) from UK primary care.
  
  
  OBJECTIVE
  To estimate the prevalence of TRD in UK primary care. Design and setting Data were collected as part of a multicentre randomised controlled trial, from 73 general practices in UK primary care.
  
  
  METHODS
  Potential participants (aged 18-75 years who had received repeated prescriptions for antidepressants) were identified from general practice records. Those who agreed to be contacted were mailed a questionnaire that included questions on depressive symptoms (Beck Depression Inventory [BDI-II]), and adherence to antidepressants. Those who scored ≥14 on the BDI-II and had taken antidepressants for at least 6 weeks at an adequate dose were defined as treatment resistant.
  
  
  RESULTS
  A total of 2439 patients completed the questionnaire (84% of those who agreed to be contacted), of whom 2129 had been prescribed an adequate dose of antidepressants for at least 6 weeks. Seventy-seven per cent (95% CI = 75% to 79%) had a BDI score of ≥14. Fifty-five per cent (95% CI = 53% to 58%) (n = 1177) met the study's definition of TRD, of whom 67% had taken their antidepressants for more than 12 months.
  
  
  CONCLUSIONS
  The high prevalence of TRD is an important challenge facing clinicians in UK primary care. A more proactive approach to managing this patient population is required to improve outcome.
authors.affiliation: School of Social and Community Medicine, University of Bristol, Bristol, UK.
authors.forename: Laura
authors.initials: L
authors.lastname: Thomas
authors.affiliation: School of Social and Community Medicine, University of Bristol, Bristol, UK.
authors.forename: David
authors.initials: D
authors.lastname: Kessler
authors.affiliation: University of Exeter Medical School, Exeter, UK.
authors.forename: John
authors.initials: J
authors.lastname: Campbell
authors.affiliation: Institute of Health and Wellbeing, General Practice and Primary Care Group, University of Glasgow, Glasgow, UK.
authors.forename: Jill
authors.initials: J
authors.lastname: Morrison
authors.affiliation: School of Clinical Sciences, University of Bristol, Bristol, UK.
authors.forename: Tim J
authors.initials: TJ
authors.lastname: Peters
authors.affiliation: Institute of Health and Wellbeing, General Practice and Primary Care Group, University of Glasgow, Glasgow, UK.
authors.forename: Chris
authors.initials: C
authors.lastname: Williams
authors.affiliation: Mental Health Sciences Unit, University College London, London, UK.
authors.forename: Glyn
authors.initials: G
authors.lastname: Lewis
authors.affiliation: Reader in epidemiology, School of Social and Community Medicine, University of Bristol, Bristol, UK.
authors.forename: Nicola
authors.initials: N
authors.lastname: Wiles
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000928:Antidepressive Agents / Q000627:therapeutic use*; D015928:Cognitive Behavioral Therapy / Q000379:methods; D003131:Combined Modality Therapy / Q000379:methods; D003430:Cross-Sectional Studies; D003866:Depressive Disorder / Q000188:drug therapy* / Q000453:epidemiology; D004351:Drug Resistance; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D006113:United Kingdom / Q000453:epidemiology; D055815:Young Adult
chemical_list: D000928:Antidepressive Agents