title: Treatment-resistant depression: resistant to definition?
abstract: OBJECTIVE
  To better define treatment-resistant depression (TRD) so as to assist clinical management and refine treatment guidelines.
  
  
  METHODS
  In this study, we examine a broad range of clinical variables in depressed patients (n=196) referred to a tertiary referral Mood Disorders Unit (MDU). Information was collected from patients, referrers and assessors over a period of 32 months and included evaluations of treatments, treatment resistance and related variables. Data were analysed across trichotomized 'high', 'low' and 'no' treatment resistance groupings of patients.
  
  
  RESULTS
  A significantly greater proportion of patients with melancholia were amongst the high TRD group, and this was consistent across different strategies for evaluating melancholia.
  
  
  CONCLUSIONS
  Melancholia perhaps provides a prototypic TRD subset that perhaps reflects some innate aspects of melancholic depression or factors such as the impact of ageing. Research into TRD is needed to both replicate this finding and perhaps explicate it further.
authors.affiliation: Black Dog Institute, Prince of Wales Medical Research Institute, Sydney, NSW, Australia. g.malhi@unsw.edu.au
authors.forename: G S
authors.initials: GS
authors.lastname: Malhi
authors.forename: G B
authors.initials: GB
authors.lastname: Parker
authors.forename: J
authors.initials: J
authors.lastname: Crawford
authors.forename: K
authors.initials: K
authors.lastname: Wilhelm
authors.forename: P B
authors.initials: PB
authors.lastname: Mitchell
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000523:psychology; D000928:Antidepressive Agents / Q000494:pharmacology*; D003430:Cross-Sectional Studies; D003866:Depressive Disorder / Q000145:classification* / Q000188:drug therapy*; D004351:Drug Resistance; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D017410:Practice Guidelines as Topic; D011379:Prognosis; D009626:Terminology as Topic
chemical_list: D000928:Antidepressive Agents