Influences of excessive smartphone use on subjective symptoms, mood, and autonomic nervous reactivity

Influences of excessive smartphone use on subjective symptoms, anxiety, mood, autonomic nervous reactivity and salivary cortisol was assessed, by examining differences in these parameters including autonomic and endocrine system responses to a psychological stressor (Mental arithmetic), between excessive and non-excessive smartphone users, and between long time use period and short time use period in each user group, in 28 female college students (18 to 23 years old). Subjective symptoms assessed by Cornell medical index (CMI), and anxiety assessed by state-trait anxiety inventory (STAI), were significantly higher in excessive users, and physical symptoms in CMI and trait anxiety in STAI reduced significantly after 2 weeks of short time use period in excessive users. Repeated measures ANOVA revealed decreased autonomic nervous reactivity to mental arithmetic assessed by heart rate variability in excessive users, but not in non-excessive users, and improved reactivity after 2 weeks of short time use period in excessive users.