Table 1 Participants’ characteristics based on age group

Sex

Male

2295 (47.9%)

2565 (49.2%)

4860 (48.6%)

Female

2496 (52.1%)

2645 (50.8%)

5141 (51.4%)

Education^*

 < middle school graduates

96 (2.0%)

1311 (25.2%)

1407 (14.1%)

High school graduates

2771 (57.8%)

3335 (64.0%)

6106 (61.1%)

 ≥ University graduates

1924 (40.2%)

564 (10.8%)

2488 (24.9%)

Monthly household income^*

 < KRW 4 million

1331 (27.8%)

3431 (65.9%)

4762 (47.6%)

KRW 4–6 million

2169 (45.3%)

1044 (20.0%)

3213 (32.1%)

 ≥ KRW 6 million

1291 (26.9%)

735 (14.1%)

2026 (20.3%)

Monthly personal income^*a

 < KRW 3 million

1782 (46.0%)

2303 (65.5%)

4085 (40.8%)

 ≥ KRW 3 million

2093 (54.0%)

1215 (34.5%)

3308 (33.1%)

Job status^*

No

912 (19.0%)

1692 (32.5%)

2604 (26.0%)

Yes

3879 (81.0%)

3518 (67.5%)

7397 (74.0%)

Area of residence^*

Metropolitan

2235 (46.6%)

2147 (41.2%)

4382 (43.8%)

City

1652 (34.5%)

1743 (33.5%)

3395 (33.9%)

Small town

904 (18.9%)

1320 (25.3%)

2224 (22.2%)

Digital literacy^*

15.05 ± 3.70

12.79 ± 4.12

13.87 ± 4.08

Psychosocial characteristics

Social relations^*

8.63 ± 1.63

8.37 ± 1.67

8.50 ± 1.68

Life satisfaction^*

20.87 ± 3.16

20.13 ± 3.37

20.49 ± 3.29

Smartphone Overdependence Scale

Self-control failure^*

6.18 ± 1.97

5.47 ± 2.12

5.81 ± 2.08

Salience^*

5.61 ± 1.99

5.10 ± 2.07

5.34 ± 2.05

Problematic consequence^*

6.49 ± 2.13

6.08 ± 2.09

6.28 ± 2.12

Risk of smartphone overdependence^*b

No-risk

3862 (80.6%)

4368 (83.8%)

8230 (82.3%)

Potential- risk

742 (15.5%)

681 (13.1%)

1423 (14.2%)

High-risk

187 (3.9%)

161 (3.1%)

348 (3.5%)

Self-awareness of smartphone dependence^*

Less dependent

1523 (31.8%)

2960 (56.8%)

4483 (44.8%)

Similar to others

2706 (56.5%)

1858 (35.7%)

4564 (45.6%)

More dependent

562 (11.7%)

392 (7.5%)

954 (9.5%)