Table 2.

Descriptive statistics and tests of group differences for sleep variables in the full sample and by diagnostic groups

	Full Sample N = 1001	No PTSD n = 946	PTSD n = 55	No MDD n = 933	MDD n = 58
% (N) with clinical levels of sleep problems (PSQI ≥ 6)	37.4 (374)	34.8 (329)	81.8 (45)***	35.0 (327)	79.3 (46)***
Global PSQI Score, M (SD)	5.51 (3.48)	5.29 (3.32)	9.38 (3.92)***	5.26 (3.25)	9.61 (4.50)***
Sleep Quality, M (SD)	0.96 (0.81)	0.91 (0.78)	1.74 (0.94)***	0.91 (0.78)	1.70 (0.94)***
Sleep Latency, M (SD)	0.85 (0.91)	0.81 (0.90)	1.58 (1.03)***	0.80 (0.89)	1.66 (0.84)***
Sleep Duration, M (SD)	1.19 (0.88)	1.17 (0.86)	1.58 (1.03)**	1.17 (0.86)	1.57 (1.06)**
Sleep Efficiency, M (SD)	0.51 (0.91)	0.49 (0.90)	0.72 (1.05)†	0.49 (0.89)	0.84 (1.17)*
Sleep Disturbance, M (SD)	1.08 (0.58)	1.04 (0.55)	1.71 (0.73)***	1.05 (0.56)	1.62 (0.67)***
Sleep Medication Use, M (SD)	0.23 (0.72)	0.21 (0.68)	0.62 (1.10)*	0.19 (0.65)	0.83 (1.26)**
Daytime Dysfunction, M (SD)	0.69 (0.78)	0.64 (0.75)	1.52 (0.90)***	0.64 (0.75)	1.47 (0.96)***

PTSD, posttraumatic stress disorder; MDD, major depressive disorder; PSQI, Pittsburgh Sleep Quality Index.

The percentages in the first row of the table change negligibly if PTSD and MDD classifications are made after excluding the sleep related symptom criteria for these disorders: 35.0% for No PTSD and 82.0% for PTSD, Fisher exact test, p < 0.001; 36.3% for No MDD; and 77.1% for MDD, Fisher exact test, p < 0.001. Descriptive statistics in the remaining rows also are negligibly changed if sleep symptoms are excluded from the PTSD and MDD prevalence calculations. T-tests and χ² tests were conducted for lower exposure versus higher exposure, no PTSD versus PTSD, and no MDD versus MDD. There were no significant differences by trauma exposure level. Significant test results are indicated in the PTSD and MDD columns.

^†p < 0.10

^*p < 0.05

^**p < 0.01

^***p < 0.001