Stress, Sleep Quality, and Academic Performance among Dental Students in Shiraz, Iran

Table 2

The mean scores of the 7 components of the PSQI.

Components	Year of study (number)	Scores (mean ± SD)
1-Subjective sleep quality	4 (46)	1.04 ± 0.66
	5 (46)	1.13 ± 0.71
	6 (46)	0.95 ± 0.63
	Total (138)	1.04 ± 0.66
2-Delays in falling asleep	4 (46)	1.15 ± 0.91
	5 (46)	1.30 ± 0.98
	6 (46)	1.34 ± 0.92
	Total (138)	1.26 ± 0.28
3-Sleep duration	4 (46)	1.17 ± 0.82
	5 (46)	0.91 ± 0.72
	6 (46)	0.71 ± 0.71
	Total (138)	2.29 ± 0.75
4-Efficiency and effectiveness of sleeping	4 (46)	0.087 ± 0.28
	5 (46)	0.26 ± 0.71
	6 (46)	0.23 ± 0.56
	Total (138)	0.19 ± 0.51
5-Sleep disorders	4 (46)	0.98 ± 0.49
	5 (46)	0.98 ± 0.49
	6 (46)	0.98 ± 0.53
	Total (138)	0.98 ± 0.50
6-Hypnotic drugs	4 (46)	0.26 ± 0.77
	5 (46)	0.30 ± 0.75
	6 (46)	0.34 ± 0.73
	Total (138)	0.30 ± 0.75
7-Inadequate performance throughout the day	4 (46)	0.95 ± 0.81
	5 (46)	1.00 ± 0.86
	6 (46)	1.15 ± 0.89
	Total (138)	1.03 ± 0.85
Total	4 (46)	5.65 ± 2.48
	5 (46)	5.89 ± 3.00
	6 (46)	5.73 ± 2.32
	Total (138)	5.76 ± 2.6