**1. Introduction**

In December 2019, COVID-19 first broke out in Wuhan city [1]. The virus could be spread by a person-to-person pattern including direct transmission, inhalation transmission and contact transmission. Afterwards, the virus quickly spread to China and the world [2]. Hence, COVID-19 was defined as a public health emergency of international concern on 30 January 2020 by the World Health Organization (WHO) and declared a pandemic on 12 March 2020 [3]. Up to 5 December 2020, there had been over 66 million reported confirmed cases of COVID-19 and 1.5 million deaths [4]. Wuhan city in the Hubei Province firstly implemented a Level 1 response to the public health emergency and a lockdown on 23 January 2020 due to the high fatality rate [1]. All public traffic was stopped and the movement of individuals was restricted. Most of the people, except for those involved in epidemic prevention and control, the police and few workers of necessary industries, were required to stay at home [5,6]. After Wuhan city, the government of all provinces in China implemented a Level 1 response to the public health emergency on 29 January 2020 [7]. Hence, all campuses of the universities in China were mandated to be closed in the spring of 2020 and the college students were required to stay at home and have their courses online to complete their academic study plan [8]. The long time of the lockdown caused people to get information, including a lot of fake news, from the media or the internet, which inevitably led to a stress response [9]. The transmission routes, origin and treatments of COVID-19 were not clearly understood at the early epidemic stage and the individual was only isolated in the home. Social interaction, physical activities and entertainment were prohibited and the normal living style was changed [10]. Meanwhile, surfing time increased and sleep and diets were irregular [11]. Thus, the long lockdown caused severe psychological symptoms such as anxiety, depression, insomnia and fear to the people isolated at home [12]. Qiu et al. carried out a survey and received 52,730 valid responses from 36 provinces as well as Hong Kong, Macau and Taiwan on 10 February 2020; they reported that 35% of the population in China experienced

psychological distress during the COVID-19 epidemic [13]. A total of 1210 respondents from 194 cities in China took part in the survey within the first two weeks of the COVID-19 outbreak and the results of Wang et al. demonstrated that 28.8% of respondents had an anxious symptom of a moderate to severe level and 16.5% experienced moderate to severe depression symptoms [14]. Mazza et al. claimed that females exhibited a greater level of distress than males and had a higher level of anxiety. In addition, the respondents of the age of 18–30 and above 60 years were easier to be affected by distress than those with an age range of 30–60 [15]. College students are in the late adolescence stage with a high neurodevelopmental risk. Moreover, the supervision or attention from parents was significantly decreased [16] and college students were more vulnerable than the adults [12]. It was found that 7.7% of students were depressive, which was higher than that of the general population during the COVID-19 pandemic [17]. Anxiety, depression, sleep difficulties and stress were regarded as the main manifestations of the psychological symptoms in the disaster [18,19]. Wang et al. reported that the psychological symptoms for college students were moderate to severe anxiety (28.8%), depression (16.5%) and stress (8.1%) [20]. Fu et al. investigated the influence of variables such as sex, age, grade, place of residence and parent's education level on the anxiety of college students and claimed that the anxiety level of the students in the rural regions was higher than that of the urban regions and that the female students experienced more anxiety than the male students due to their biology [21].

In this paper, a cross-sectional online survey was designed to acquire the mental state of college students in a university of science and technology located in Wuhan city during the lockdown and the impact of the residence region (urban or rural), grade, gender and annual household income on the psychological symptoms was assessed. The survey results will help the office of student affairs to understand the mental state of the students. Based on previous publications, it was hypothesized that:

**Hypothesis 1.** *There is a significant difference of psychological symptoms with regard to the gender.*

**Hypothesis 2.** *There is a significant difference of psychological symptoms with regard to the residence.*

**Hypothesis 3.** *There is a significant difference of psychological symptoms with regard to the annual household income.*
