Table 1. Epidemiological characteristics of study subjects.
| Variables | Frequency (%) or Mean (SD) | |
|---|---|---|
| Sex (M/F) | 234 (48)/253 (52) | |
| Grades (first/second/third) | 264 (54.2)/113 (23.2)/110 (22.6) | |
| SES (top/mid/bot) | 55 (11.3)/418 (85.8)/14 (2.9) | |
| Total | 487 | |
| Smartphone addiction | 31.59 (7.43) | |
| Depression | 5.62 (5.05) | |
| ADHD | 10.68 (9.90) | |
| Positive parenting attitude | 31.45 (5.36) | |
| Negative parenting attitude | 24.17 (6.82) | |
| Perceived stress | 26.96 (6.58) | |
| Interpersonal relationship problems | 86.43 (26.93) | |
| Smartphone usage type | ||
| Call, text message | 3.83 (1.01) | |
| Study | 2.37 (0.91) | |
| Information finding | 3.23 (1.07) | |
| Music/movies | 4.50 (0.80) | |
| Social network service | 4.06 (1.18) | |
| Game | 3.27 (1.30) | |
| Others (shopping etc.) | 2.96 (1.13) | |
SD = standard deviation, M = male, F = female, SES = socio-economic status, Smartphone addiction = a youth smartphone addiction self-diagnosis scale, Depression = the Korean version of the patient health questionnaire-9, ADHD = attention deficit hyperactivity disorde, Positive parenting attitude = parenting attitude scale devised by Heo, Negative parenting attitude = parenting attitude scale devised by Heo, Stress = the perceived stress scale, Interpersonal relationship problems = the short form of the Korean-inventory of interpersonal problems circumplex scale.
Smartphone usage type scale: call, text message, study, information finding, music/movies, social network service, game, others, shopping etc.