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Table 2 Sleep characteristics in adolescents with and without delayed sleep phase syndrome (DSPS) in the ung@hordaland study (n = 9,338)

From: Delayed sleep phase syndrome in adolescents: prevalence and correlates in a large population based study

  No DSPS (n = 9032) DSPS (n = 306)   
  Mean SD Mean SD P- level Cohen’s d
Weekdays       
 Bedtime 23:17 00:59 23:46 01:04 < .001 0.42
 Risetime 06:47 00:40 07:00 00:48 < .001 0.30
 Time in bed 07:30 01:00 07:14 01:07 < .001 −0.20
 Sleep duration 06:27 01:38 05:41 01:21 < .001 −0.45
 Sleep efficiency (%) 84.8% 18.21 78.0% 13.2 < .001 −0.43
 Oversleeping (“most days” or “always”) 5.0% 21.8 27.6% 44.8 < .001 0.64
Weekends       
 Bedtime 01:31 01:29 02:07 01:16 < .001 0.35
 Risetime 11:13 01:31 12:09 01:17 < .001 0.61
 Time in bed 09:41 01:23 10:01 01:06 < .001 0.28
 Sleep duration 08:38 01:52 08:28 01:05 .168 −0.07
Week days/weekends       
 Sleep onset latency 00:47 00:57 01:21 00:50 < .001 0.62
 Wake after sleep onset 00:14 00:38 00:11 00:23 .130 −0.16
 Subjective sleep need 08:34 01:52 09:09 01:58 < .001 0.25
 Sleep deficiency (weekdays) 02:07 02:29 03:28 02:22 < .001 −0.48
 Sleep deficiency (weekends) 00:04 02:30 −00:40 02:12 < .001 −0.25
 Sleepiness (days per week) 2.25 2.05 3.09 2.21 < .001 0.39
 Tiredness (days per week) 3.68 1.86 4.87 1.80 < .001 0.65
Differences between weekdays and weekends       
 Bedtime 02:27 02:17 02:21 00:59 .434 −0.09
 Risetime 04:26 01:36 05:28 01:23 < .001 0.42
 Sleep duration 02:11 01:33 02:47 01:25 < .001 0.38