Validation of the three-factor model of the PSQI in a large sample of chronic fatigue syndrome (CFS) patients

Department of General Internal Medicine, Infectious Diseases and Psychosomatic Medicine, University Hospital Ghent, Belgium.
Journal of psychosomatic research (Impact Factor: 2.74). 02/2012; 72(2):111-3. DOI: 10.1016/j.jpsychores.2011.11.004
Source: PubMed


To evaluate whether a 3-factor model of the Pittsburgh Sleep Quality Index (PSQI) scale would fit the constellation of sleep disturbances in patients with a diagnosis of chronic fatigue syndrome (CFS).
Consecutive CFS patients filled out the PSQI. Scores from this self-report questionnaire were examined with exploratory and confirmatory factor analysis (CFA).
413 CFS patients were included for analysis in this study. CFA showed that the 7 PSQI component scores clustered into the 3 factors reported by Cole et al. (2006), i.e. Sleep Efficiency, Perceived Sleep Quality and Daily Disturbances. In contrast with the single-factor and all 2-factor models, all factor loadings were significant, and all goodness-of-fit values were acceptable.
In CFS, the PSQI operates as a 3-factor scoring model as initially seen in healthy and depressed older adults. The separation into 3 discrete factors suggests the limited usefulness of the global PSQI as a single factor for the assessment of subjective sleep quality, as also evidenced by a low Cronbach's alpha (0.64) in this patient sample.

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Available from: Liesbeth Delesie, Oct 10, 2015
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    • "), critical as to move away from a focus on fatigue by including positive indicators of energy. Overall, the separation of the PSQI into three distinct factors underscores the claim from previous studies that the global PSQI has limited usefulness as a single factor (Mariman et al., 2012). Indeed, a more heterogeneous approach involves the recognition that sleep and day-related parameters can be distinguished and that, in turn, sleep outcomes can be differentiated into more refined categories. "
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    Personality and Individual Differences 04/2015; 77. DOI:10.1016/j.paid.2015.01.003 · 1.86 Impact Factor
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    • "The PSQI is composed of 19 items, which are combined into seven components that are summarized into a global score that represents a unidimensional sleep quality construct [5]. However, five recent studies [6-10] have questioned the appropriateness of using only the global score. In 2006, Cole et al. examined PSQI structure by exploratory and confirmatory factor analysis in healthy and depressed elderly adults and showed initial evidence that a single global PSQI score did not capture the multidimensional nature of sleep disturbances when examined by PSQI [6]. "
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    • "Accordingly, Cole et al. derived a three-factor model of the PSQI: sleep efficiency (comprising PSQI components: sleep efficiency and sleep duration), perceived sleep quality (comprising PSQI components: use of sleep medication, sleep latency, and subjective sleep quality), and daily disturbances (comprising PSQI components: daytime dysfunction and sleep disturbance). This model has been used in a range of community studies with young and older adults, and in people with chronic fatigue syndrome (Aloba, Adewuya, Ola, & Mapayi, 2007; Cole et al., 2006; Mariman et al., 2012). The short form of the Depression Anxiety and Stress Scale (DASS–21; Lovibond & Lovibond , 1995) measures the frequency of these core negative symptoms over the past week. "
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