title: Psychometric evaluation of the internalized stigma of mental illness scale for patients with mental illnesses: measurement invariance across time.
abstract: BACKGROUND
  The current investigation examined the psychometric properties of the Internalized Stigma of Mental Illness (ISMI) scale in a sample of patients with mental illness. In addition to the internal consistency, test-retest reliability, and concurrent validity that previous studies have tested for the ISMI, we extended the evaluation to its construct validity and measurement invariance using confirmatory factor analysis (CFA).
  
  
  METHODS
  Three hundred forty-seven participants completed two questionnaires (i.e., the ISMI and the Depression and Somatic Symptoms Scale [DSSS]), and 162 filled out the ISMI again after 50.23±31.18 days.
  
  
  RESULTS
  The results of this study confirmed the frame structure of the ISMI; however, the Stigma Resistance subscale in the ISMI seemed weak. In addition, internal consistency, test-retest reliability, and concurrent validity were all satisfactory for all subscales and the total score of the ISMI, except for Stigma Resistance (α = 0.66; ICC = 0.52, and r = 0.02 to 0.06 with DSSS). Therefore, we hypothesize that Stigma Resistance is a new concept rather than a concept in internalized stigma. The acceptable fit indices supported the measurement invariance of the ISMI across time, and suggested that people with mental illness interpret the ISMI items the same at different times.
  
  
  CONCLUSIONS
  The clinical implication of our finding is that clinicians, when they design interventions, may want to use the valid and reliable ISMI without the Stigma Resistance subscale to evaluate the internalized stigma of people with mental illness.
authors.affiliation: Department of Psychiatry, Chi Mei Medical Center, Tainan, Taiwan; Health Service and Population Research Department, Institute of Psychiatry, King's College London, London, United Kingdom; Department of Senior Citizen Service Management, College of Recreation and Health Management, Chia Nan University of Pharmacy and Science, Tainan, Taiwan.
authors.forename: Chih-Cheng
authors.initials: CC
authors.lastname: Chang
authors.affiliation: Department of Psychiatry, Chi Mei Medical Center, Liouying, Tainan, Taiwan.
authors.forename: Tsung-Hsien
authors.initials: TH
authors.lastname: Wu
authors.affiliation: Department of Senior Citizen Service Management, College of Recreation and Health Management, Chia Nan University of Pharmacy and Science, Tainan, Taiwan; Department of Nursing, College of Health Sciences, Chang Jung Christian University, Tainan, Taiwan.
authors.forename: Chih-Yin
authors.initials: CY
authors.lastname: Chen
authors.affiliation: Deparment of Public Health, College of Medicine, National Chen Kung University, Tainan, Taiwan; Departments of Internal Medicine and Occupational and Environmental Medicine, National Cheng Kung University Hospital, Tainan, Taiwan.
authors.forename: Jung-Der
authors.initials: JD
authors.lastname: Wang
authors.affiliation: Deparment of Public Health, College of Medicine, National Chen Kung University, Tainan, Taiwan.
authors.forename: Chung-Ying
authors.initials: CY
authors.lastname: Lin
mesh_terms: D000328:Adult; D005163:Factor Analysis, Statistical; D005260:Female; D006801:Humans; D008297:Male; D001523:Mental Disorders / Q000523:psychology*; D008875:Middle Aged; D011594:Psychometrics; D013240:Stereotyping