title: Somatoform dissociation among Swedish adolescents and young adults: the psychometric properties of the Swedish versions of the SDQ-20 and SDQ-5.
abstract: BACKGROUND
  Somatoform dissociation is supposed to be a vital aspect of the general concept of dissociation. The Somatoform Dissociation Questionnaire-20 (SDQ-20) and the brief version SDQ-5 are self-report instruments constructed to identify somatic dissociation.
  
  
  OBJECTIVE
  In the present study, the psychometric qualities of the Swedish version of the SDQ-20 and its brief version, the SDQ-5, were examined among adolescents and young adults. Reliability and concurrent validity were investigated.
  
  
  METHODS
  A total of 512 adolescents and young adults participated in the study: 461 adolescents from a non-clinical sample and 50 adolescents and young adults from a clinical eating disorder outpatient unit. They completed the self-report instruments the SDQ-20, the SDQ-5 (part of SDQ-20), the Linköping Youth Life Experience Scale (LYLES, a trauma history scale) and the Dissociation Questionnaire-Sweden (Dis-Q-Sweden).
  
  
  RESULTS
  Both internal consistency and test-retest reliability of the Swedish version of SDQ-20 were good in both the non-clinical (α = 0.83) and the clinical groups (α = 0.84); the reliability for the SDQ-5 was, however, lower (non-clinical α = 0.50, clinical α = 0.64). Significant differences were found between the clinical and non-clinical groups on both somatoform and psychoform dissociation. Correlations between the Dis-Q-Sweden, SDQ-20 and SDQ-5 were generally high. The criterion and convergent validity was acceptable for both scales but somewhat better for SDQ-20 than for SDQ-5.
  
  
  CONCLUSIONS
  The advantage with both the SDQ-20 and the SDQ-5 is that they are short questionnaires, but the results suggests that SDQ-20 is preferable based on the higher-quality psychometric properties of the SDQ-20.
authors.affiliation: Department for Behavioral Sciences and Learning, Section for Clinical Psychology, Linköping University , SE-581 83 Linköping , Sweden.
authors.forename: Doris
authors.initials: D
authors.lastname: Nilsson
authors.forename: Annika
authors.initials: A
authors.lastname: Lejonclou
authors.forename: Carl Göran
authors.initials: CG
authors.lastname: Svedin
authors.forename: Mattias
authors.initials: M
authors.lastname: Jonsson
authors.forename: Rolf
authors.initials: R
authors.lastname: Holmqvist
mesh_terms: D000293:Adolescent; D004213:Dissociative Disorders / Q000175:diagnosis*; D005260:Female; D006801:Humans; D008016:Life Change Events; D008297:Male; D011569:Psychiatric Status Rating Scales; D011594:Psychometrics; D015203:Reproducibility of Results; D057566:Self Report; D013001:Somatoform Disorders / Q000175:diagnosis*; D011795:Surveys and Questionnaires; D013548:Sweden; D055815:Young Adult
keywords: Adolescents; Psychometrics; SDQ-20; Self-assessment; Somatoform dissociation