title: Assessing psychological distress in patients with skin diseases: reliability, validity and factor structure of the GHQ-12.
abstract: OBJECTIVE
  We studied reliability, validity and factor structure of the 12-item General Health Questionnaire (GHQ-12) in dermatological patients.
  
  
  METHODS
  Subjects attending a dermatological outpatient clinic were administered the GHQ-12 and the Skindex-29. A random subsample was mailed another copy of the questionnaires to be completed within 1 week.
  
  
  RESULTS
  A total of 2,579 subjects completed the GHQ-12. The internal consistency of the GHQ-12 was high (Cronbach's alpha = 0.88). Test-retest reliability on 137 subjects was also fairly satisfactory (intraclass correlation coefficient = 0.72), notwithstanding a re-test artefact probably related to reassurance from the physician. Evidence of construct validity was provided by the pattern of correlation between scores on the GHQ-12 and on the scales of Skindex-29, which were as hypothesized. Also, GHQ-12 scores of patients in different clinical groups varied as hypothesized, with patients affected by inflammatory skin diseases scoring significantly higher than patients with isolated skin lesions. We obtained both a two-factor and a three-factor solution: the latter seemed theoretically more appropriate, although the first may have practical advantages. A 'social dysfunction' factor emerged in both analyses, while the other items loaded on a 'general dysphoria' factor or on two separate factors interpreted as 'anxiety' and 'loss of self-esteem'.
  
  
  CONCLUSIONS
  The GHQ-12 is a reliable and valid instrument with a factor structure that is quite stable across different samples as well as across diverse cultures. Its brevity and easiness of completion make it a useful tool to assess psychological distress in dermatological patients.
authors.affiliation: Clinical Epidemiology Unit, Dermatological Institute IDI-IRCCS, Rome, Italy. a.picardi@idi.it
authors.forename: A
authors.initials: A
authors.lastname: Picardi
authors.forename: D
authors.initials: D
authors.lastname: Abeni
authors.forename: P
authors.initials: P
authors.lastname: Pasquini
mesh_terms: D000293:Adolescent; D000328:Adult; D017677:Age Distribution; D000368:Aged; D002908:Chronic Disease; D015331:Cohort Studies; D005260:Female; D006801:Humans; D007558:Italy / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D010358:Patient Participation; D011788:Quality of Life; D015203:Reproducibility of Results; D018570:Risk Assessment; D012307:Risk Factors; D012494:Sampling Studies; D012720:Severity of Illness Index; D017678:Sex Distribution; D012871:Skin Diseases / Q000175:diagnosis / Q000453:epidemiology / Q000523:psychology*; D018709:Statistics, Nonparametric; D013315:Stress, Psychological; D011795:Surveys and Questionnaires