Table 3.

Mean (SD) factorial scores and p-values for sleep questionnaire items in CFS and non-fatigued subjects

Factor pattern on sleep questionnaire items	CFS (n = 35)	NF (n = 40)	P *
	Mean factor scores (SD)†	Mean factor scores (SD)
F1 Insomnia	0.54 (0.8)	-0.48 (0.9)	.000
"How often trouble sleeping", "Waking up before you wanted to", "Sleeping for less than 5 hours", "Difficulty falling asleep", "Repeated awakenings", "Waking up not feeling refreshed", "Restlessness during sleep"
F2 Sleepiness	0.27 (1.2)	-0.24 (0.5)	.060
"Falling asleep while sitting and talking", "Falling asleep while doing something, such as driving or talking", "Falling asleep in a car while stopped in traffic", "Falling asleep while sitting and reading", "Falling asleep as a passenger in a car", "Falling asleep while sitting quietly after a lunch", "Falling asleep while sitting inactive in a public place", "Trouble staying awake"
F3 Physical/Somatic	0.54 (1.0)	-0.48 (0.5)	.001
"Nightmares or waking up frightened or crying out loud", "Waking up with aches, pains, or stiffness", "Sleeping more than nine hours", "Taking medication for sleep"
F4 Apnea "Interruptions to your breathing during sleep", "Falling asleep while lying down to rest in the afternoon"	0.09 (0.7)	-0.08 (1.2)	.865
F5 Body Clock	0.13 (1.2)	-0.11 (0.7)	.610
"Working shifts", "Irregular bed time and/or wake-up time during the work week or weekdays"
F6 Nasal Obstruction	0.13 (1.1)	-0.12 (0.8)	.318
"Loud snoring"

* 2-factor ANOVA, controlling for medication that influences sleep.

^† A higher factor score represents more agreement on the sleep questionnaire items comprising the factor (i.e. more sleep complains)