Table 1.

Demographic data of patients with primary insomnia (PI) and healthy controls (HC).

	PI	HC	P value
Number of subjects	35	35
Gender (male/female)	5/35	9/26	0.23a
Age in years (M, SD)	39.3, 8.6	34.9, 10.7	0.067b
Total PQSI (M, SD)	12.57, 3.93	2.26, 1.36	4.52e − 23c

M = mean, SD = standard deviation, and PQSI = Pittsburgh Sleep Quality Index.

^aThe P value was obtained with a Chi-square test.

^bThe P value was obtained with a two-tailed two-sample t-test.

^cThe P value was obtained with a one-tailed two-sample t-test.