Table 1 Basic Statistics on Sample and Socio-demographic Characteristics of Participants

Time range

Nov 2015 to Jan 2017

Dec 2016 to Jan 2017

Nov 2015 to Jan 2016

Dec 2015 to Jan 2016

Location

Three cities

Wuhan

Ningbo

Shiyan

Composition

Medic

Postgraduates, undergraduates

Junior college students

Medical workers

Sampling method

Two ways

Convenient sampling

Stratified random sampling

Stratified random sampling

Response rates

2798/2999 (93.30)

122/130 (93.85)

1453/1519 (95.66)

1223/1350 (90.59)

 Male

397 (14.19)

42 (34.43)

20 (1.38)

335 (27.39)

 Female

2401 (85.81)

80 (65.57)

1433 (98.62)

888 (72.61)

Age, years

24.97 ± 7.53

23.47 ± 2.65

19.58 ± 1.09

31.51 ± 7.07

PSQ Index

0.429 ± 0.155

0.402 ± 0.133^a

0.399 ± 0.138

0.466 ± 0.168

PSS

–

15.689 ± 4.863^a

–

–

 Negative feelings

–

9.734 ± 3.506^a

–

–

 Positive feelings

–

5.955 ± 2.051^a

–

–

SF-8

–

–

–

65.255 ± 17.097

 PCS

–

–

–

67.145 ± 17.745

 MCS

–

–

–

63.364 ± 18.924

GADS

–

–

8.081 ± 4.349

10.850 ± 4.691

 GAS

–

–

4.503 ± 2.442

5.935 ± 2.460

 GDS

–

–

3.577 ± 2.343

4.915 ± 2.620