. 2011 Apr 15;7(2):196–203.

Table 1.

Demographic and general self-report variables

Variable	Insomnia (n = 65) Mean (SD)	Control (n = 29) Mean (SD)	Statistic (t (df))	p value
Demographics & Medical Status
Age	36.6 (9.1)	30.0 (8.8)	−3.27 (92)	0.002^*
Gender (% female)	55.4%	72.4%	X² = 2.44 (1)	0.12
Ethnicity (% Caucasian)	90.6% (n = 58/64)	82.8%	Fisher exact p = 0.31
BMI	26.0 (4.9) n = 62	23.4 (3.6)	−2.53 (89)	0.01^*
Prescription drug use (% yes)	44.6%	37.9%	X² = 0.37 (1)	0.55
Apnea-hypopnea index^a	2.3 (2.1) n = 63	2.4 (3.1) n = 27	-0.12 (88)	0.91
Sleep-Wake and Circadian
Pittsburgh Sleep Quality Index	11.4 (3.3)	2.1 (1.0)	-21.11 (83.95)^**	< 0.001^*
Epworth Sleepiness Scale	7.5 (3.9) n = 64	4.4 (3.1)	−3.69 (91)	< 0.001^*
Composite Scale of Morningness	33.1 (8.7)	38.6 (5.9)	3.52 (75.55)^**	< 0.001^*
Multidimensional Fatigue Inventory (General)	13.4 (3.2)	7.0 (2.0)	−11.65 (80.81)^**	< 0.001^*
Pittsburgh Sleep Diary
Sleep latency (min)^c	35.6 (33.6) n = 64	9.1 (7.5)	−7.82 (91)	< 0.001^*
Total sleep time (min)	368.8 (68.9) n = 64	447.8 (63.3)	5.25 (91)	< 0.001^*
Wake after sleep onset (min)^b	38.9 (29.9) n = 64	3.7 (4.2)	−11.56 (90.36)^**	< 0.001^*
Sleep efficiency (%)^d	82.7 (11.3) n = 64	97.2 (2.4)	−11.69 (41.88)^**	< 0.001^*
Sleep quality	44.2 (13.1) n = 64	77.5 (10.2)	12.13 (91)	< 0.001^*
Psychological Status
Inventory of Depressive Symptomatology	16.4 (6.0) n = 64	5.2 (6.1)	−8.31 (91)	< 0.001^*
Beck Inventory for Anxiety^b	4.1 (3.9)	1.2 (1.6)	−4.94 (75.03)^**	< 0.001^*
Penn State Worry Questionnaire	31.6 (14.6)	21.1 (14.0)	−3.27 (92)	0.002^*

Means and standard deviations reported in their original units.

p < 0.05

^**

Satterthwaite method used due to unequal variances

LN(X+.1) transformation used in the analyses

SQRT(X+.1) transformation used in the analyses

LN(X) transformation used in the analyses

LN(100-X) transformation used in the analyses