title: Assessment of the factor structure and reliability of the Portuguese version of the General Health Questionnaire-28 among adults.
abstract: BACKGROUND
  The General Health Questionnaire (GHQ, Goldberg & Hillier, 1979 , Psychological Medicine, 9, 139-145) is a self-administered questionnaire used to measure non-psychotic psychiatric disorders. There is a study using a Portuguese version of this questionnaire (n = 60) including a group of inpatients with infectious diseases (Ribeiro & Antunes, 2003 , Revista Portuguesa de Psicossomática, 5(1), 37-45), but there are no larger studies in non-clinical Portuguese population.
  
  
  OBJECTIVE
  The primary aim of the study was to confirm the psychometric properties of the Portuguese version of the GHQ-28 among 171 Portuguese adults in non-clinical settings.
  
  
  METHODS
  The Portuguese version of the GHQ-28 was administered to 171 adult subjects of Portuguese general population.
  
  
  RESULTS
  The Portuguese version of the GHQ-28 has an internally consistent measure Cronbach's α 0.922 for the GHQ-28 total scale. For the subscale somatic symptoms Cronbach's α was 0.825; for the subscale Anxiety/ Insomnia, Cronbach's α was 0.873; for the subscale Social dysfunction Cronbach's α was 0.873 and for the subscale Severe Depression was 0.838. Four factors were extracted using factor analysis: somatic symptoms (items 1-7); anxiety/insomnia (items 8-14); psychosocial dysfunction (items 15-21); and severe depression (items 22-28).
  
  
  CONCLUSIONS
  The findings suggest that the GHQ-28 is a suitable screening instrument for adult Portuguese population in non-clinical settings.
authors.affiliation: Nursing School of Coimbra, Rua 5 de Outubro, Coimbra, Portugal. anapaula@esenfc.pt
authors.forename: Ana Paula Teixeira
authors.initials: AP
authors.lastname: De Almeida Vieira Monteiro
mesh_terms: D000328:Adult; D005163:Factor Analysis, Statistical; D005260:Female; D006801:Humans; D008297:Male; D001523:Mental Disorders / Q000175:diagnosis*; D008603:Mental Health; D008875:Middle Aged; D011174:Portugal; D011594:Psychometrics; D015203:Reproducibility of Results; D011795:Surveys and Questionnaires / Q000592:standards*; D014175:Translating; D055815:Young Adult