Markus Jansson-Fröjmark1, Shane MacDonald. 1. Department of Behavioral, Social, and Legal Sciences, Orebro University, Orebro, Sweden. markus.jansson@bsr.oru.se
Abstract
OBJECTIVES: The purpose of this study was to examine the factorial solution of the Modified Somatic Perception Questionnaire (MSPQ) among individuals with insomnia symptoms in the general population. DESIGN: A cross-sectional study with a randomly selected sample from the general population (N = 3600; 20-60 year old) was used. In total, 251 of the 2179 respondents fulfilled the criteria for insomnia symptoms and filled out a survey on demographic parameters, the MSPQ, the Hospital Anxiety and Depression Scale, sleep medication use and health care consumption. METHODS: Exploratory factor analysis and correlations were used. RESULTS: The results showed that a two-factor solution, accounting for 47.31% of the variance, was extracted from the 13 items of the MSPQ. Although one factor consisting of 10 items determined general symptoms of somatic arousal (alpha = 0.83), the other factor with three items assessed stomach symptoms and nausea (alpha = 0.78). The two factors were significantly inter-correlated (r = 0.54) and significantly associated with the total MSPQ (r = 0.96, r = 0.74). The two factors also showed discriminant validity with anxiety and depression and predictive validity with retrospective reports of sleep medication use and health care consumption. A few significant interactions emerged the two MSPQ factors and degree of sleep complaints. CONCLUSIONS: Although it is often assumed that the MSPQ taps a single factor of somatic arousal, this study on individuals with insomnia symptoms suggests that a two-factor solution has the best fit. Further research on the factorial solution of the MSPQ is warranted.
OBJECTIVES: The purpose of this study was to examine the factorial solution of the Modified Somatic Perception Questionnaire (MSPQ) among individuals with insomnia symptoms in the general population. DESIGN: A cross-sectional study with a randomly selected sample from the general population (N = 3600; 20-60 year old) was used. In total, 251 of the 2179 respondents fulfilled the criteria for insomnia symptoms and filled out a survey on demographic parameters, the MSPQ, the Hospital Anxiety and Depression Scale, sleep medication use and health care consumption. METHODS: Exploratory factor analysis and correlations were used. RESULTS: The results showed that a two-factor solution, accounting for 47.31% of the variance, was extracted from the 13 items of the MSPQ. Although one factor consisting of 10 items determined general symptoms of somatic arousal (alpha = 0.83), the other factor with three items assessed stomach symptoms and nausea (alpha = 0.78). The two factors were significantly inter-correlated (r = 0.54) and significantly associated with the total MSPQ (r = 0.96, r = 0.74). The two factors also showed discriminant validity with anxiety and depression and predictive validity with retrospective reports of sleep medication use and health care consumption. A few significant interactions emerged the two MSPQ factors and degree of sleep complaints. CONCLUSIONS: Although it is often assumed that the MSPQ taps a single factor of somatic arousal, this study on individuals with insomnia symptoms suggests that a two-factor solution has the best fit. Further research on the factorial solution of the MSPQ is warranted.