RT Article T1 Decreases in psychological well-being among American adolescents after 2012 and links to screen time during the rise of smartphone technology JF Emotion VO 18 IS 6 SP 765 OP 780 A1 Twenge, Jean M. 1971- A2 Campbell, William Keith A2 Martin, Gabrielle N. LA English YR 2018 UL https://krimdok.uni-tuebingen.de/Record/191250684X DO 10.1037/emo0000403