Variable

Author

Expected

relationship

Age

Dale et al. (2015), Shehnaz et al. (2014)

Binge drinking

Skarstein et al. (2014)

Bullied

Skarstein et al. (2016)

Coffee consumption

Skarstein et.al. (2014)

Conflict with parents

Skarstein et al. (2016)

Physical pain

Dale et al. (2015), Hansen et al. (2008), Hasseleid et al. (2017), Levin et al. (2015), Skarstein et al. (2016), Shehnaz et al. (2014), Skarstein et al.(2014), Turunen et al. (2005)

Educational ambition

Skarstein et al. (2014)

Female gender

Bäckryd (2018), Dale et al. (2015), Hasseleid et al. (2017), Shehnaz et al. (2014)

Health

Du and Knopf (2009), Levin et al. (2015)

Household income

Du and Knopf (2009)

Maternal education

Du and Knopf (2009), Shehnaz et al. (2014)

Mood

Turunen et al. (2005)

Need to feel successful

Skarstein et al. (2016)

Parental usage

Andersen et al. (2012), Hasseleid et al. (2017), Jensen (2014)

Physical activity

Dale et al. (2015)

Self-esteem

Skarstein et al. (2014)

Shirking school

Skarstein et al. (2014)

Sleep problems

Skarstein et al. (2014)

Spare-time work

Skarstein et al. (2014)

Stress

Hansen et al. (2008), Skarstein et al. (2016)

Unemployment

Turunen et al. (2005)