Table 3.

Descriptive statistics for sleep outcomes across Period 1 and Period 2 of sleep.

	Placebo		Zolpidem		Placebo		Zolpidem
	Baseline phase		Baseline phase		Chronic phase		Chronic phase		Significance
	Mean	(SE)	Mean	(SE)	Mean	(SE)	Mean	(SE)
Sleep Period 1
Initial sleep latency (min)	12.04	3.72	8.29	2.42	12.45	2.28	8.06	1.46	-
Wake after sleep onset (min)	1.14	0.43	2.33	2.05	5.64	2.37	0.72	0.41	-
Total sleep time (min)	42.55	3.00	44.74	2.35	38.55	3.68	45.91	2.59	-
Sleep efficiency*	0.78	0.06	0.82	0.04	0.69	0.06	0.84	0.03	Z>P
Stage 1 (%)*	0.16	0.06	0.07	0.02	0.18	0.05	0.07	0.01	Z<P
Stage 2 (%)+	0.33	0.04	0.43	0.06	0.50	0.06	0.44	0.07	1<2
slow wave sleep (%)	0.51	0.06	0.48	0.07	0.32	0.07	0.47	0.06	-
REM sleep (%)	0.00	0.00	0.02	0.02	0.00	0.00	0.02	0.02	-
Sleep Period 2
Initial sleep latency (min)*	10.58	2.29	2.71	0.70	22.04	9.43	2.31	0.61	Z<P
Wake after sleep onset (min)	28.84	8.15	26.13	6.80	32.71	7.64	35.94	9.56	-
Total sleep time (min)	387.30	8.18	393.13	8.22	372.12	10.34	389.53	9.47	-
Sleep efficiency	0.91	0.02	0.93	0.02	0.87	0.03	0.91	0.02	-
Stage 1 (%)*	0.09	0.02	0.05	0.01	0.09	0.02	0.06	0.01	Z<P
Stage 2 (%)*	0.49	0.02	0.53	0.03	0.50	0.02	0.54	0.02	Z>P
slow wave sleep (%)+	0.13	0.02	0.13	0.02	0.10	0.02	0.11	0.02	1>2
REM sleep (%)	0.30	0.02	0.29	0.02	0.31	0.02	0.29	0.01	-
REM latency (min)	55.29	10.03	68.77	11.80	58.30	9.53	56.40	10.84	-

Note. SE = standard error. Significance: P = Placebo, Z = Zolpidem, 1 = baseline phase, 2 = chronic phase.

Symbols:

dash (-) = not significant;

asterisk (*) = main effect of drug condition;

plus sign (+) = main effect of phase.