Sleep in relation to psychiatric symptoms and perceived stress in Swedish adolescents aged 15 to 19 years

FIGURE 1.

The results from the single items “Minutes of sleep per night”, part of the subscale Sleep duration, and “Problems staying awake last month”, part of the subscale Daytime dysfunction, divided by sex

		Total	Female	Male	Missing data on sex	p-value between sexes
Minutes of sleep per night	mean (CI 95%)	492 (484-500)	495 (485-505)	483 (467-498)		0.11
	SD	57.4	59.2	54.5
	range	330-810	330-810	385-615
	n	198	139	49	10
	n < 8h	54	35	17	2	0.2
	% < 8h	27%	25%	35%
Problems staying awake	n never	79	55	22	2
	n less than 1 time/week	65	46	15	4
	n 1 to 2 times/week	38	26	9	3
	n 3 or more times/week	18	14	3	1
	n > 1 to 2 times/week	56	40	12	4	0.6
	n total	200	141	49	10
	% > 1 to 2 times/week	28%	28.4%	24.5%

The items in the subscale Sleep disturbance from Pittsburgh Sleep Quality Index (PSQI) by sex Item from PSQI Subscale Sleep Disturbance

Item from PSQI Subscale Sleep Disturbance		Female	Male	p-value between sexes
No sleep in 30 min	mean	1.47	1.27	0.143
	CI 95 %	(1.27-1.66)	(0.97-1.56)
	n	141	49
Nightly wakening	n	141	49
	mean	1.10	0.53	0.0003
	CI 95 %	(0.93-1.27)	(0.3-0.76)
Toilet visits	mean	0.65	0.41	0.0491
	CI 95 %	(0.50-0.81)	(0.2-0.62)
	n	141	49
Breathing difficulties	mean	0.2	0.22	0.6116
	CI 95 %	(0.11-0.28)	(0.03-0.42)
	n	141	49
Snoring/coughing	mean	0.25	0.14	0.1394
	CI 95 %	(0.15-0.35)	(-0.01-0.3)
	n	141	49
Feeling cold	mean	1.0	0.5	0.0006
	CI 95 %	(0.88-1.23)	(0.28-0.74)
	n	140	49
Feeling hot	n	139	48
	mean	0.93	0.63	0.0297
	CI 95 %	(0.76-1.09)	(0.38-0.87)
Unpleasant dreams	mean	0.81	0.23	<0.001
	CI 95 %	(0.66-0.97)	(0.08-0.38)
	n	139	48
Ache	mean	0.33	0.1	0.0241
	CI 95 %	(0.21-0.45)	(0.01-0.23)
	n	139	49
Other	mean	0.59	0.5	0.2781
	CI 95 %	(0.44-0.75)	(0.21-0.79)
	n	138	48

The results of the subscales from the Pittsburgh Sleep Quality Index in Swedish adolescents by sex

Subscales of PSQI		Total	Female	Male	Missing data on sex	p-value between sexes
Sleep quality	mean	1.27	1.28	1.18		p = 0.20
	CI 95%	(1.17-1.37)	(1.17-1.40)	(0.96-1.41)
	n	200	141	49	10
Sleep latency	mean	1.5	1.53	1.37		p = 0.17
	CI 95%	(1.35-1.65)	(1.35-1.71)	(1.10-1.63)
	n	200	141	49	10
Sleep duration	mean	0.82	0.8	0.82		p = 0.55
	CI 95%	(0.72-0.92)	(0.68-0.92)	(0.59-1.04)
	n	202	141	49	12
Habitual sleep efficiency	mean	0.39	0.36	0.42		p = 0.68
	Cl 95%	(0.28-0.49)	(0.24-0.48)	(0.2-0.63)
	n	199	139	48	12
Sleep disturbance	mean	1.08	1.14	0.91		p= 0.0020
	CI 95%	(1.01-1.15)	(1.06-1.22)	(0.79-1.04)
	n	188	132	46	10
Use of sleeping medication	mean	0.11	0.09	0.1		p = 0.55
	Cl 95%	(0.05-0.18)	(0.02-0.16)	(-0.02-0.22)
	n	200	141	49	10
	n using	13	8	3	2
Daytime dysfunction	mean	1.54	1.54	1.43		p = 0.19
	CI 95%	(1.43-1.64)	(1.41-1.66)	(1.21-1.65)
	n	200	141	49	10
	n affected	187	133	44
	% affected	93.5%	94.3%	89.8%

Spearman correlations between overall sleep quality (Pittsburgh Sleep Quality Index [PSQI]) and general mental health (Global Severity Index from Symptoms Checklist 90 [GSI]) as well as perceived stress (Perceived Stress Scale [PSS]), by sex

Scales	All			Female			Male
	ρ	n	p-value	ρ	n	p-value	ρ	n	p-value
PSQI–GSI	0.4393	179	< 0.0001	0.4137	129	< 0.0001	0.4375	44	0.0030
PSQI–PSS	0.4802	166	< 0.0001	0.4437	122	< 0.0001	0.6032	40	< 0.0001

The results of Pittsburgh Sleep Quality Index (PSQI) in 185 Swedish adolescents by sex

PSQI	Totala	Femaleb	Maleb	Missing data on sex	p-value between sexes
n	185	130	45	10
Mean score CI 95%	6.70 (6.30-7.20)	6.72 (6.23-7.21)	6.31 (5.41-7.21)		p = 0.20
n > score 5	140	99	32		p = 0.50
% > score 5	76%	76%	71%
p-value mean score>score 5	p< 0.0001	p< 0.0001	p= 0.0026