Table 1

Descriptive statistics for well-being scores and explanatory variables under study, by gender

	Total	Boys		Girls
	N	N	Mean (SD)/%	N	Mean (SD)/%	P values
Full sample (N %)	120 115	57 153	47.58%	62 962	52.42%
WEMWBS scores	117 842	56 352	47.82%	61 490	52.18%	<0.0001
Mean (SD)			50 (8.60)		45 (9.66)
Substance use*	71 133	32 516	45.71%	38 617	54.29%	<0.0001
None		17 133	52.69	19 932	51.61
One		10 783	33.16	12 150	31.46
Two		3010	9.26	3785	9.8
Three		1590	4.89	2750	7.12
Unhealthy eating habits†	115 918	55 289	47.70%	60 629	52.30%	<0.0001
None		12 081	21.85	11 951	19.71
One		20 287	36.69	20 389	33.63
Two		16 373	29.61	19 064	31.44
Three		6548	11.84	9225	15.22
Sleeping hours (>8 hours)	117 516	56, 207	47.83%	61 307	52.17%	<0.0001
Not in the past 7 days		3676	6.54	6922	11.29
Some days		11 051	19.66	16 051	26.18
Most days		20, 121	35.8	20 928	34.14
Everyday		21, 361	38	17 406	28.39
Bullying	117 744	56 309	47.82%	61 435	52.18%	<0.0001
No		45 959	81.62	45 094	73.40
yes		10 350	18.38	16 341	26.60
Physical activity	118 450	56 674	47.85	61 776	52.15	<0.0001
Physically active		48 172	85	44 348	71.79
Inactive		8502	15	17 428	28.21
Screen time	118 845	56 892	47.87	61 943	52.13%	<0.0001
About 2 hours/day		3609	6.34	3469	5.6
≤1 hours/day		912	1.6	929	1.5
About 3–4 hours/day		18 621	32.73	17 311	27.95
About 5–6 hours/day		17 198	30.23	17 850	28.82
≥7 hours/day		16 559	29.1	22 387	36.14
Reading	118 140	56 513	47.84	61 627	52.16	<0.0001
None		14 278	25.26	9875	16.02
About Half an hour/day		17 572	31.09	15 363	24.93
About 1 hour/day		12 505	22.13	13 442	21.81
≥ 2 hours/day		12 158	21.51	22947	37.24

Figures in bold refer to full sample distribution, the proportion of males and females in the study.
*Risk behaviours include smoking, drinking and cannabis use.
†Unhealthy eating habits include skipping breakfast, not having five portions of fruits and vegetables and consumption of takeaway food.
WEMWBS, Warwick-Edinburgh Mental Wellbeing score.