title: Reliability and validity of the Thai self-report version of the Yale-Brown Obsessive-Compulsive Scale-Second Edition.
abstract: OBJECTIVE
  The self-report version of the Yale-Brown Obsessive-Compulsive Scale (Y-BOCS) has been developed to overcome the limitations of the clinician-administered version, which needs to be executed by trained personnel and is time consuming. The second edition of the Y-BOCS (Y-BOCS-II) was developed to address some limitations of the original version. However, there is no self-report version of the Y-BOCS-II at the moment. This study aimed to evaluate the psychometric properties of the developed Thai self-report version of the Yale-Brown Obsessive-Compulsive Scale-Second Edition (Y-BOCS-II-SR-T).
  
  
  METHODS
  Y-BOCS-II-SR-T was developed from the Thai version of the Yale-Brown Obsessive-Compulsive Scale-Second Edition (Y-BOCS-II-T). The Y-BOCS-II-SR-T, the Y-BOCS-II-T, the Thai version of the Florida Obsessive-Compulsive Inventory (FOCI-T), the Hamilton Rating Scale for Depression (HAM-D), the nine-item Patient Health Questionnaire (PHQ-9), and the Pictorial Thai Quality of Life (PTQL) instrument were administered to 52 obsessive-compulsive disorder (OCD) patients. Internal consistency for the Y-BOCS-II-SR-T was calculated with Cronbach's alpha coefficient (α), and the factor analyses were completed. Pearson's correlation was used in determining convergent and divergent validity among the other measures.
  
  
  RESULTS
  The mean score of the Y-BOCS-II-SR-T total score was 20.71±11.16. The internal consistencies of the Y-BOCS-II-SR-T total scores, the obsession subscale, and the compulsion subscale scores were excellent (α=0.94, α=0.90, and α=0.89, respectively). The correlation between each item and the Y-BOCS-II-SR-T total score showed strong correlation for all items. Confirmatory factor analysis with model modification showed adequate fit for obsession and compulsion factor models. The Y-BOCS-II-SR-T had strong correlation with the YBOCS-II-T and the FOCI-T (r s>0.90) and weaker correlation with the HAM-D, PHQ-9, and PTQL (r s<0.60), which implied good convergent and divergent validity.
  
  
  CONCLUSIONS
  The Y-BOCS-II-SR-T is a psychometrically sound and valid measure for assessing obsessive-compulsive symptoms.
authors.affiliation: Department of Psychiatry, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok, Thailand.
authors.forename: Thanita
authors.initials: T
authors.lastname: Hiranyatheb
authors.affiliation: Department of Psychiatry, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok, Thailand.
authors.forename: Ratana
authors.initials: R
authors.lastname: Saipanish
authors.affiliation: Department of Psychiatry, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok, Thailand.
authors.forename: Manote
authors.initials: M
authors.lastname: Lotrakul
authors.affiliation: Department of Psychiatry, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok, Thailand.
authors.forename: Rungthip
authors.initials: R
authors.lastname: Prasertchai
authors.affiliation: Department of Psychiatry, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok, Thailand.
authors.forename: Wanwisa
authors.initials: W
authors.lastname: Ketkaew
authors.affiliation: Department of Psychiatry, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok, Thailand.
authors.forename: Sudawan
authors.initials: S
authors.lastname: Jullagate
authors.affiliation: Section for Clinical Epidemiology and Biostatistics, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok, Thailand.
authors.forename: Umaporn
authors.initials: U
authors.lastname: Udomsubpayakul
authors.affiliation: Department of Psychiatry, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok, Thailand.
authors.forename: Pichaya
authors.initials: P
authors.lastname: Kusalaruk
keywords: Thai; Yale-Brown Obsessive-Compulsive Scale; obsessive-compulsive disorder; self-report