One Major Side Effect of Staring at Your Phone Too Much One Major Side Effect of Staring at Your Phone Too Much The term "smartphone addiction," like "sugar addiction," may not be a medically recognized condition, but that hasn't stopped scientists from aggressively studying the effects of smartphone use on those who are overly attached to their devices—most notably young adults and children. So far, the results aren't pretty. A study of five- to eight-year-olds published last year in the Journal of Clinical Sleep Medicine found that "excessive smartphone use was related to shorter total sleep time in children," and "use of a smartphone was also associated with significant reductions in the quality of sleep in younger children."