title: Measuring insight through patient self-report: an in-depth analysis of the factor structure of the Birchwood Insight Scale.
abstract: Little research has focused on item analysis and factor structure of the most commonly used measures of insight. We examined the factorial structure of the Birchwood Insight Scale (BIS), a brief, easy-to-administer, self-report measure. We studied the BIS in 327 first-episode psychosis patients, including a test sample (n=163) and a validation sample (n=164). We then used data from 100 patients with chronic serious mental illnesses as a second, external validation sample. Exploratory factor analysis was conducted with the test subsample, and confirmatory factor analyses with the two validation samples. Confirmatory factor analyses (in both the first-episode psychosis validation sample and the chronic serious mental illness sample) indicated that a single-factor solution, with seven items loading on a single factor-with item 1 ("Some of your symptoms are made by your mind") eliminated-was the best-fitting model. Seven of the eight original BIS items loading on a single factor fit the data well in these samples. Researchers using this efficient measure of patient-reported insight should assess the item distributions and factor structure of the BIS in their samples, and potentially consider eliminating item 1.
authors.affiliation: The George Washington University School of Public Health and Health Services, Department of Epidemiology and Biostatistics, Washington, DC, USA.
authors.forename: Sean D
authors.initials: SD
authors.lastname: Cleary
authors.affiliation: The George Washington University School of Medicine and Health Sciences, Department of Psychiatry and Behavioral Sciences, Washington, DC, USA.
authors.forename: Sanaa
authors.initials: S
authors.lastname: Bhatty
authors.affiliation: Lenox Hill Hospital, Department of Psychiatry, 111 E. 77th Street, New York, NY, USA.
authors.forename: Beth
authors.initials: B
authors.lastname: Broussard
authors.affiliation: Emory University School of Medicine, Department of Psychiatry and Behavioral Sciences, Atlanta, GA, USA.
authors.forename: Sarah L
authors.initials: SL
authors.lastname: Cristofaro
authors.affiliation: Emory University School of Medicine, Department of Psychiatry and Behavioral Sciences, Atlanta, GA, USA.
authors.forename: Claire Ramsay
authors.initials: CR
authors.lastname: Wan
authors.affiliation: Lenox Hill Hospital, Department of Psychiatry, 111 E. 77th Street, New York, NY, USA; Hofstra North Shore-LIJ School of Medicine at Hofstra University, Department of Psychiatry, Hempstead, NY, USA. Electronic address: mcompton@nshs.edu.
authors.forename: Michael T
authors.initials: MT
authors.lastname: Compton
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001364:Awareness; D005163:Factor Analysis, Statistical; D005260:Female; D006801:Humans; D008297:Male; D001523:Mental Disorders / Q000523:psychology; D008875:Middle Aged; D008960:Models, Psychological; D011581:Psychological Tests; D011618:Psychotic Disorders / Q000523:psychology*; D015203:Reproducibility of Results; D012565:Schizophrenic Psychology; D057566:Self Report; D055815:Young Adult
keywords: Awareness of illness; Birchwood Insight Scale; First-episode psychosis; Insight; Psychosis; Schizophrenia; Serious mental illness