Table 4.

Results of planned comparisons across groups according to precipitating event type.

	Nontraumatic Events vs. No Events	Traumatic Events vs. No Events	Traumatic Events vs. Nontraumatic Events
Insomnia (ISI Total Score)	2.28 (0.23, 4.33) p = .029, d = 0.44	3.42 (1.17, 5.67) p = .003, d = 0.66	1.14 (−0.21, 2.50) p = .098, d = 0.22
Sleep Quality (PSQI Total Score)	0.65 (−0.83, 2.12) p = .39, d = 0.17	1.68 (0.06, 3.30) p = .042, d = 0.46	1.03 (0.053, 2.01) p = .039, d = 0.28
Diary Sleep Efficiency (%)	−1.53 (−7.14, 4.08) p = .59, d = −0.11	−1.46 (−7.66, 4.74) p = .64, d = ?0.11	0.07 (−3.68, 3.83) p = .97, d = 0.005
Objective Sleep Efficiency (%)	−1.04 (−4.41, 2.32) p = .54, d = −0.13	−0.13 (−3.84, 3.58) p = .95, d = −0.015	0.91 (−1.30, 3.12) p = .42, d = 0.11
Duration of Sleep Problems (Years)	−0.49 (−4.78, 3.81) p = .82, d = −0.042	4.22 (−0.47, 8.91) p = .078, d = 0.37	4.70 (1.88, 7.53) p = .001, d = 0.41
Nightmare Frequency (Nights/Week)	0.74 (−0.53, 2.00) p = .25, d = 0.25	1.04 (−0.35, 2.44) p = .14, d = 0.35	0.30 (−0.52, 1.13) p = .47, d = 0.10
PTSD (PCL-5 Total Score)	9.39 (0.05, 18.73) p = .049, d = 0.42	18.25 (7.97, 28.53) p = .001, d = 0.83	8.86 (2.90, 14.83) p = .004, d = 0.40
Depression (PHQ-9 Total Score)	1.96 (−0.44, 4.35) p = .11, d = 0.33	3.38 (0.73, 6.02) p = .012, d = 0.57	1.42 (−0.15, 2.99) p = .075, d = 0.24

Note. Tabled values show differences in adjusted means, 95% confidence interval for the difference, p value of the comparison, and the effect size expressed as Cohen’s d.

Number of observations vary according to variable, from n = 299 to n = 321; ISI = Insomnia Severity Index, PSQI = Pittsburgh Sleep Quality Index, PCL-5 = PTSD Checklist-5, and PHQ-9 = Patient Health Questionnaire-9. Lower values indicate poorer sleep efficiency and greater PSQI scores indicate poorer sleep quality; analyses controlled for the following covariates: age, race/ethnicity, years of education, income, relationship status, and employment status.