TABLE 1.

Description of the measures of mental wellbeing, school demands, teacher support and classmate support. Swedish Health Behaviour in School-aged Children study 2017/18. (Sweden. 2017/2018).

Scale	Items	Response categories	Original index range	Truncated index range	Eigenvalue	Factor loadings	Cronbach’s α
Mental wellbeing (SWEMWBS)	a. “I’ve been feeling optimistic about the future”	a-g.	7–35 a	-	3.86	0.67–0.82	0.90
	b. “I’ve been feeling useful”	1 = “None of the time”
	c. “I’ve been feeling relaxed”	2 = “Rarely”
	d. “I’ve been dealing with problems well”	3 = “Some of the time”
	e. “I’ve been thinking clearly”	4 = “Often”
	f. “I’ve been feeling close to other people”	5 = “All of the time”
	g. “I’ve been able to make up my mind about things”
School demands	a. “How pressured do you feel by the schoolwork you have to do?”	a.	3–14	5–12	1.26	0.55–0.71	0.72
	b. “I find the schoolwork difficult”	1 = “Not at all”
	c. “The schoolwork makes me tired”	2 = “A little”
		3 = “Some”
		4 = “A lot”
		b-c.
		1 = “Almost never”
		2 = “Seldom”
		3 = “Sometimes”
		4 = “Often”
		5 = “Very often”
Teacher support	a. “I feel that my teachers accept me as I am”	a-c.	3–15	8–15	1.95	0.79–0.83	0.86
	b. “I feel that my teachers care about me as a person”	1 = “Strongly disagree”
	c. “I feel a lot of trust in my teachers”	2 = “Disagree”
		3 = “Neither agree nor disagree”
		4 = “Agree”
		5 = “Strongly agree”
Classmate support	a. “The students in my class(es) enjoy being together”	a-c.	3–15	8–15	1.65	0.69–0.78	0.82
	b. “Most of the students in my class(es) are kind and helpful”	1 = “Strongly disagree”
	c. “Other students accept me as I am”	2 = “Disagree”
		3 = “Neither agree nor disagree”
		4 = “Agree”
		5 = “Strongly agree”

^a Transformed scale was used in the analyses (see Stewart-Brown et al. [42]).