Table 2.

Comparison between smartphone non-user, low smartphone use, and high smartphone use groups

	Smartphone non-user group n = 71 Mean ± SD	Low smartphone use group n = 121 Mean ± SD	High smartphone use group n = 127 Mean ± SD	p (a/b/c)
BDI	6.0 (3.0–12.0)	5.0 (2.0–9.0)	8.0 (4.0–14.0)	=0.001 (0.05/0.15/<0.001)
BAI	7.0 (3.0–13.0)	5.0 (2.0–10.0)	9.0 (3.0–15.0)	<0.001 (0.02/0.29/<0.001)
PSQI Subscales
Subjective Sleep quality	1.0 (1.0–1.0)	1.0 (1.0–1.0)	1.0 (1.0–1.0)	0.13 (0.31/0.48/0.04)
Sleep latency	1.0 (0.0–2.0)	1.0 (0.0–1.0)	1.0 (0.0–1.0)	0.58 (0.42/0.89/0.34)
Sleep duration	1.0 (0.0–2.0)	1.0 (0.0–2.0)	0.0 (0.0–1.0)	0.35 (0.61/0.48/0.14)
Sleep efficiency	0.0 (0.0–0.0)	0.0 (0.0–0.0)	0.0 (0.0–0.0)	0.85 (0.58/0.68/0.88)
Sleep disturbance	1.0 (1.0–2.0)	1.0 (1.0–1.0)	1.0 (1.0–1.0)	0.06 (0.02/0.37/0.12)
Use of sleep medication	0.0 (0.0–0.0)	0.0 (0.0–0.0)	0.0 (0.0–0.0)	0.48 (0.43/0.23/0.65)
Daytime dysfunction	1.0 (0.0–1.0)	1.0 (0.0–1.0)	1.0 (0.0–2.0)	0.011 (0.17/0.15/0.003)
PSQI global score	5.0 (4.0–7.0)	4.0 (3.0–6.0)	5.0 (3.0–7.0)	0.179 (0.12/0.93/0.10)

Median (25th percentile–75th percentile)

BDI: Beck Depression Inventory, BAI: Beck Anxiety Inventory, PSQI: Pittsburgh Sleep Quality Index, SD: Standard Deviation

p: p value for Kruskal–Wallis

p ≤ 0.017 is accepted as statistically significant since Bonferroni correction was applied for two groups comparisons

a: p value between smartphone non-user group and low smartphone use group

b: p value between smartphone non-user group and high smartphone use group

c: p value between low smartphone use group and high smartphone use group