The approach selected herein with regard to comorbidity was consistent with the broader sleep-research literature which emphasizes insomnia without comorbidities (i.e., primary insomnia) from insomnia with comorbidities (i.e., secondary insomnia).
The female preponderance in the present study was surprising given the higher male ratio in the study by Thorpy et al. [ 12], although a more even gender balance was found in a broader delayed sleep phase study from Norway [ 13].
In the broadest sense, sleep is defined as a period of inactivity accompanied by an increase in arousal threshold and, if disrupted, is followed by a period of sleep rebound (Hendricks and Sehgal, 2004; Huber et al., 2004).
However, four of the five language groups were comfortable with a broader approach to sleep disturbance suggesting either 'difficulty sleeping at night, or trouble with sleeping' as a broader category.
We considered the PHQ-9 item content more appropriate since it covers a broader spectrum of sleep problems.
The PHQ9 approach, to include a broader description of sleeping problems in the item, results in an adequate measurement capacity ("trouble falling or staying asleep, or sleeping too much").
By the mid-20th century, scientists were engaged in study of the cognitive and neurological mechanisms of dreaming, one part of a broader scientific exploration of sleep.
EDS is not a disorder in and of itself, but represents symptoms of several broad conditions including poor sleep quality, depression, anxiety, sleep-disordered breathing, and obesity metabolic syndrome [14].
"That's the kind of broad architecture of your sleep across the night," Epsie says.
In the broader context, this REM-sleep modulation of negative aversive memories may hold implications for the mechanistic understanding and treatment of mood disorders, including major depression.
In order to shed light on the social determinants of sleep, a broad approach simultaneously covering a variety of indicators of sociodemographic and socioeconomic factors across life course is needed.
