Table 2.

Pre- and post-treatment mean ± SDs of sleep, sleepiness, and depression symptoms between DSPD adolescents undergoing CBT plus BLT (N = 23) or in a Waitlist (WL) control condition (N = 17)

	Pre-treatment		Post-treatment		Effect size (d)
	CBT plus BLT	WL	CBT plus BLT	WL
Sleep onset latency (min)
school*	78.1 ± 41.0	78.8 ± 31.3	22.2 ± 12.8	65.3 ± 42.0	1.13
weekend*	68.5 ± 42.3	62.7 ± 37.2	26.1 ± 18.7	52.6 ± 43.7	0.65
Sleep onset time (clock time)
school*	00:06 ± 67.2min	23:48 ± 69.4min	23:28 ± 58.8min	00:10 ± 65.3min	0.89
weekend*	00:56 ± 84.6min	00:09 ± 62.1min	23:45 ± 60.0min	00:37 ± 78.9min	1.24
Total sleep time (h)
school*	7.1 ± 1.3	6.9 ± 1.4	8.1 ± 0.6	6.9 ± 1.1	0.81
weekend	8.3 ± 1.5	8.4 ± 1.6	8.4 ± 1.0	8.1 ± 1.7	0.22
WASO (min)*	26.6 ± 27.5	14.6 ± 22.6	4.6 ± 7.2	16.1 ± 19.2	1.14
Rise time (clock time)
school*	07:32 ± 33.0min	07:22 ± 28.9min	07:06 ± 27.5min	07:29 ± 40.1min	0.92
weekend*a	09:28 ± 81.6min	09:22 ± 63.2min	08:42 ± 72.8min	09:33 ± 56.8min	0.92
Discrepant rise time (h)	1.8 ± 1.2	2.0 ± 1.1	1.3 ± 1.0	2.1 ± 1.0	0.45
Daytime sleepiness (0-32)*	20.4 ± 4.8	18.1 ± 4.4	14.0 ± 3.6	16.0 ± 3.7	0.79
Fatigue (0-31)*	17.2 ± 1.2	16.6 ± 1.3	10.2 ± 1.2	14.9 ± 1.3	0.75
Depression symptoms (0-26)	7.6 ± 3.6	7.4 ± 5.5	3.9 ± 2.8	6.2 ± 4.5	0.71

^*significant interaction (i.e., significant improvement in CBT plus BLT group vs. WL group) with P < 0.05; effect sizes are: d < 0.20 = small, d < 0.50 = moderate, d < 0.80 = large;

^adespite the mean weekend rise time of ∼09:30, many parents placed some limits on their adolescents' sleep-in, and when adolescents slept-in on their first day of light therapy they often slept till after 10:30. Process variables = sleep onset time and rise time; Primary outcome variables = sleep onset latency, total sleep time, daytime sleepiness; Secondary outcome variables = fatigue, depression symptoms.