title: The London field trial for hoarding disorder.
abstract: BACKGROUND
  A new diagnostic category, hoarding disorder (HD), has been proposed for inclusion in DSM-5. This study field-tested the validity, reliability and perceived acceptability of the proposed diagnostic criteria for HD. Method Fifty unselected individuals with prominent hoarding behavior and 20 unselected, self-defined 'collectors' participated in thorough psychiatric assessments, involving home visits whenever possible. A semi-structured interview based on the proposed diagnostic criteria for HD was administered and scored by two independent raters. 'True' diagnoses were made by consensus according to the best-estimate diagnosis procedure. The percentage of true positive HD cases (sensitivity) and true negative HD cases (specificity) was calculated, along with inter-rater reliability for the diagnosis and each criterion. Participants were asked about their perceptions of the acceptability, utility and stigma associated with the new diagnosis.
  
  
  RESULTS
  Twenty-nine (58%) of the hoarding individuals and none of the collectors fulfilled diagnostic criteria for HD. The sensitivity, specificity and inter-rater reliability of the diagnosis, and of each individual criterion and the specifiers, were excellent. Most participants with HD (96%) felt that creating a new disorder would be very or somewhat acceptable, useful (96%) and not too stigmatizing (59%).
  
  
  CONCLUSIONS
  The proposed HD criteria are valid, reliable and perceived as acceptable and useful by the sufferers. Crucially, they seem to be sufficiently conservative and unlikely to overpathologize normative behavior. Minor changes in the wording of the criteria are suggested.
authors.affiliation: Department of Psychosis Studies, King's College London, Institute of Psychiatry, London, UK. david.mataix-cols@kcl.ac.uk
authors.forename: D
authors.initials: D
authors.lastname: Mataix-Cols
authors.forename: D
authors.initials: D
authors.lastname: Billotti
authors.forename: L
authors.initials: L
authors.lastname: Fernández de la Cruz
authors.forename: A E
authors.initials: AE
authors.lastname: Nordsletten
mesh_terms: D003937:Diagnosis, Differential; D039721:Diagnostic and Statistical Manual of Mental Disorders; D005260:Female; D000067836:Hoarding Disorder / Q000175:diagnosis* / Q000523:psychology; D006686:Hobbies / Q000523:psychology*; D006801:Humans; D007406:Interview, Psychological; D008131:London; D008297:Male; D008875:Middle Aged; D017060:Patient Satisfaction / Q000706:statistics & numerical data; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D057545:Social Stigma