title: Measuring Acceptance of Sleep Difficulties: The Development of the Sleep Problem Acceptance Questionnaire.
abstract: OBJECTIVE
  Acceptance may be an important therapeutic process in sleep medicine, but valid psychometric instruments measuring acceptance related to sleep difficulties are lacking. The purpose of this study was to develop a measure of acceptance in insomnia, and to examine its factor structure as well as construct validity.
  
  
  METHODS
  In a cross-sectional design, a principal component analysis for item reduction was conducted on a first sample (A) and a confirmatory factor analysis on a second sample (B). Construct validity was tested on a combined sample (C).
  
  
  METHODS
  Questionnaire items were derived from a measure of acceptance in chronic pain, and data were gathered through screening or available from pretreatment assessments in four insomnia treatment trials, administered online, via bibliotherapy and in primary care.
  
  
  METHODS
  Adults with insomnia: 372 in sample A and 215 in sample B. Sample C (n = 820) included sample A and B with another 233 participants added.
  
  
  METHODS
  Construct validity was assessed through relations with established acceptance and sleep scales.
  
  
  RESULTS
  The principal component analysis presented a two-factor solution with eight items, explaining 65.9% of the total variance. The confirmatory factor analysis supported the solution. Acceptance of sleep problems was more closely related to subjective symptoms and consequences of insomnia than to diary description of sleep, or to acceptance of general private events.
  
  
  CONCLUSIONS
  The Sleep Problem Acceptance Questionnaire (SPAQ), containing the subscales "Activity Engagement" and "Willingness", is a valid tool to assess acceptance of insomnia.
authors.affiliation: Department of Psychology, Uppsala University, Uppsala, Sweden.
authors.forename: Kristoffer
authors.initials: K
authors.lastname: Bothelius
authors.affiliation: Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Susanna
authors.initials: S
authors.lastname: Jernelöv
authors.affiliation: Department of Psychology, Uppsala University, Uppsala, Sweden.
authors.forename: Mats
authors.initials: M
authors.lastname: Fredrikson
authors.affiliation: Health Psychology Section, Psychology Department, Institute of Psychiatry, King's College London, London, UK.
authors.forename: Lance M
authors.initials: LM
authors.lastname: McCracken
authors.affiliation: Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Viktor
authors.initials: V
authors.lastname: Kaldo
mesh_terms: D000223:Adaptation, Psychological; D000328:Adult; D001638:Bibliotherapy; D059350:Chronic Pain / Q000523:psychology; D003430:Cross-Sectional Studies; D005163:Factor Analysis, Statistical; D005260:Female; D006801:Humans; D020407:Internet; D008297:Male; D008875:Middle Aged; D011320:Primary Health Care; D025341:Principal Component Analysis; D011594:Psychometrics / Q000379:methods*; D015203:Reproducibility of Results; D057566:Self Report; D012890:Sleep / Q000502:physiology; D007319:Sleep Initiation and Maintenance Disorders / Q000503:physiopathology / Q000523:psychology*; D011795:Surveys and Questionnaires / Q000592:standards
keywords: Sleep Problem Acceptance Questionnaire; acceptance; experiential avoidance; insomnia; principal component analysis; psychometric evaluation; scale construction; willingness