*2.1. Participants*

In this study, 1480 students aged between 12 and 17 years old (students from grades seven to ten, respectively) were included ( *<sup>M</sup>*age = 14.21; *SD* = 1.22). They were from seven middle schools from the federal states of Bremen, Berlin, and Brandenburg in Germany. In terms of gender, 50.3% (*n* = 744) were girls. Regarding migration background, 9.7% (*n* = 144) reported that German was not the main language spoken at home. Around 33.6% (*n* = 483) of students reported living in families of low affluence, 33% (*n* = 474) in families of middle affluence, and 33.4 % (*n* = 479) in families of high affluence.
