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Sleep. 2011 Apr 1;34(4):531-9.

Moving beyond average values: assessing the night-to-night instability of sleep and arousal in DSM-IV-TR insomnia subtypes.

Author information

1
University of Murcia, Murcia, Spain.

Abstract

STUDY OBJECTIVES:

We explored differences between individuals with DSM-IV-TR diagnoses of primary insomnia (PI) and insomnia related to a mental disorder (IMD) by using serial measurements of self-reported sleep variables (sleep onset latency, SOL; wake after sleep onset, WASO; total sleep time, TST; sleep efficiency, SE), and visual analogue scale ratings of 2 forms of bedtime arousal (cognitive and emotional). Furthermore, we sought to examine the relationship between sleep and arousal within each diagnostic subgroup.

DESIGN:

Between-group and within-group comparisons.

SETTING:

Duke and Rush University Medical Centers, USA.

PARTICIPANTS:

One hundred eighty-seven insomnia sufferers (126 women, average age 47.15 years) diagnosed by sleep specialists at 2 sleep centers as PI patients (n=126) and IMD patients (n=61).

INTERVENTIONS:

N/A.

MEASUREMENTS AND RESULTS:

Multilevel models for sleep measures indicated that IMD displayed significantly more instability across nights in their TST (i.e., larger changes) than did PI patients. With respect to pre-sleep arousal, IMD patients exhibited higher mean levels of emotional arousal, as well as more instability on the nightly ratings of this measure. Within the PI group, correlational analyses revealed a moderate relationship between the 2 arousal variables and SOL (r values 0.29 and 0.26), whereas the corresponding correlations were negligible and statistically nonsignificant in the IMD group.

CONCLUSIONS:

We found a number of differences on nighttime variables between those diagnosed with primary insomnia and those diagnosed with insomnia related to a mental disorder. These differences imply different perpetuating mechanisms involved in their ongoing sleep difficulties. Additionally, they support the categorical distinctiveness and the concurrent validity of these insomnia subtypes.

KEYWORDS:

DSM-IV-TR; arousal; concurrent validity; insomnia related to a mental disorder; instability; measurement; primary insomnia

PMID:
21461332
PMCID:
PMC3065264
DOI:
10.1093/sleep/34.4.531
[Indexed for MEDLINE]
Free PMC Article

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