Andrew Lepp et al., 2016 Computers in Human Behavior anxiety estudio Andrew Lepp et al., 2016 Studies anxiety A study Computers and Human Behavior study estudio study study ease feelings of anxiety Computers in Human Behavior Kent State University in Ohio anxiety Computers in Human Behavior February 2014: 31; 343 - 350 studie study anxiety anxiety Computers in Human Behavior February 2014: 31; 343–350 study impactar negativamente as relações sociais diretamente ligada One 2014 study study Research heavy smartphone use and increased anxiety