title: Treatment-resistant depression in primary care across Canada.
abstract: OBJECTIVE
  Treatment-resistant depression (TRD) represents a considerable global health concern. The goal of the InSight study was to investigate the prevalence of TRD and to evaluate its clinical characterization and management, compared with nonresistant depression, in primary care centres.
  
  
  METHODS
  Physicians completed a case report on a consecutive series of patients with major depressive disorder (n = 1212), which captured patient demographics and comorbidity, as well as current and past medication.
  
  
  RESULTS
  Using failure to respond to at least 2 antidepressants (ADs) from different classes as the definition of TRD, the overall prevalence was 21.7%. There were no differences in prevalence between men and women or among ethnicities. Patients with TRD had longer episode duration, were more likely to receive polypharmacy (for example, psychotropic, lipid-lowering, and antiinflammatory agents), and reported more AD related side effects. Higher rates of disability and comorbidity (axes I to III) were associated with treatment resistance. Obesity and being overweight were also associated with treatment resistance. While the selection and sequencing of pharmacotherapy by family physicians in this sample was in line with recommendations from evidence-based treatment guidelines, the wait time to make a change in treatment was 6 to 8 weeks in both groups, which exceeds guideline recommendations.
  
  
  CONCLUSIONS
  These real-world data demonstrate the high prevalence of TRD in primary care settings, and underscore the substantial burden of illness associated with TRD.
authors.affiliation: Student, Departments of Pharmaceutical Sciences and Neuroscience, University of Toronto, Toronto, Ontario; Clinical Research Coordinator, Department of Psychiatry, University Health Network, Toronto, Ontario.
authors.forename: Sakina J
authors.initials: SJ
authors.lastname: Rizvi
authors.affiliation: Chief Operating Officer and Chief Financial Officer, Canadian Heart Research Centre, Toronto, Ontario.
authors.forename: Etienne
authors.initials: E
authors.lastname: Grima
authors.affiliation: Statistician, Canadian Heart Research Centre, Toronto, Ontario.
authors.forename: Mary
authors.initials: M
authors.lastname: Tan
authors.affiliation: Project Manager, Department of Psychiatry, University Health Network, Toronto, Ontario.
authors.forename: Susan
authors.initials: S
authors.lastname: Rotzinger
authors.affiliation: Director of Primary Care Initiatives, Canadian Heart Research Centre, Toronto, Ontario.
authors.forename: Peter
authors.initials: P
authors.lastname: Lin
authors.affiliation: Psychiatrist, Department of Psychiatry, University Health Network, Toronto, Ontario; Professor, Department of Psychiatry, University of Toronto, Toronto, Ontario; Professsor, Department of Pharmacology, University of Toronto, Toronto, Ontario.
authors.forename: Roger S
authors.initials: RS
authors.lastname: Mcintyre
authors.affiliation: Psychiatrist, Department of Psychiatry, University Health Network, Toronto, Ontario; Professor, Department of Psychiatry, University of Toronto, Toronto, Ontario; Professor, Institute of Medical Sciences, University of Toronto, toronto, Ontario.
authors.forename: Sidney H
authors.initials: SH
authors.lastname: Kennedy
mesh_terms: D000328:Adult; D000928:Antidepressive Agents / Q000009:adverse effects / Q000627:therapeutic use*; D002170:Canada; D015897:Comorbidity; D003430:Cross-Sectional Studies; D003865:Major Depressive Disorder / Q000175:diagnosis / Q000188:drug therapy* / Q000453:epidemiology* / Q000523:psychology; D061218:Depressive Disorder, Treatment-Resistant / Q000175:diagnosis / Q000188:drug therapy* / Q000453:epidemiology* / Q000523:psychology; D057915:Drug Substitution; D004359:Drug Therapy, Combination; D005260:Female; D019983:Guideline Adherence; D006306:Health Surveys; D006801:Humans; D008297:Male; D008875:Middle Aged; D011320:Primary Health Care / Q000706:statistics & numerical data*; D012189:Retrospective Studies
chemical_list: D000928:Antidepressive Agents