Coronavirus disease 2019 (COVID-19) initially outbroke in Wuhan, China in December 2019 and promptly became a pandemic worldwide within the following two months. The public health emergencies resulting from COVID-19 are negatively impacting the mental health of the population and increasing the incidence of psychological crises (Xiang et al., 2020). Early identification of populations in the first stages of psychological crisis will allow for the efficient implementation of interventional strategies (National Health Commission of China 2020). The clinical characteristics of psychological distress have not been well established across the populations affected by the COVID-19 pandemic, although a general increased level of mental distress has been reported from both the general public and frontline medical personnel (Kang et al., 2020; Qiu et al., 2020). Therefore, we designed a pilot and cross-sectional study to identify the characteristics of psychological distress across populations affected by the COVID-19 pandemic. The app-based, anonymous questionnaire was designed to survey the level of psychological distress, and the study was conducted in the Zhongshan, one of prefecture-level cities in Guangdong province, P. R. China, from February 15 to February 29, 2020. A total of 205 participants responded and completed the questionnaires. The Chinese version 9-item General Health Questionnaire (GHQ-9) and 7-item Generalized Anxiety Disorder (GAD-7) scale were employed to evaluate the prevalence and severity of psychological distress within patients newly recovery from COVID-19 infection, individuals under quarantine, and the general public. A total score of ≥10 for both the PHQ-9 and GAD-7 was defined as depression and anxiety respectively. The severity of psychological distress was classified with the standard thresholds: Minimal or none (0-4), Mild (5-9), Moderate (10-14), Severe (>15) for both the PHQ-9 and GAD-7. An increased prevalence of depression (29.2%) was found predominately in patients who experienced COVID-19 infection (p = 0.016), while the prevalence of anxiety was not statistically different across the three groups (p = 0.154) as shown in Table 1 . Trends for an increased prevalence of depression comorbid with anxiety (p = 0.086) were identified in both patients who experienced COVID-19 infection (21.1%) and the general public (22.4%) compared to those in quarantine. Both patients who experienced COVID-19 infection (19.3%) and the general public (14.3%) also had a greater proportion of severe depressive symptom (p = 0.002) as shown in Table 1. Moreover, patients who experienced COVID-19 infection and the general public more likely to demonstrate depressed mood (p = 0.038) and somatic symptoms (all p < 0.01) in the sub-items of the PHQ-9, compared to individuals under quarantine . Anxiety-like behavior, including becoming easily annoyed or irritable, manifested primarily in the general public and patients who experienced COVID-19 infection (p < 0.01). Table 1 Demographic and clinical characteristics of patients who experienced COVID-19 infection, individuals under quarantine, and the general public Patients who experienced COVID-19 infection (n=57) Individuals under quarantine(n=50) General public (n=98) F/χ2 P value Gender n (%) 6.57 0.037 Male 29 (50.9) 27 (54.0) 34 (34.7)a Female 28 (49.1) 23 (46.0) 64 (65.3)a Age (years) 46.9±15.37 b 36.2±10.91 29.6±12.69b 30.80 <0.001 Educational Level n (%)** 6.80 0.147 Junior middle school or less 17 (30.9) 13 (26.0) 41 (41.8) Senior middle school 15 (27.3) 16 (32.0) 16 (16.3) College or more 23 (41.8) 21 (42.0) 41 (41.8) Marital status n (%) 21.69 <0.001 Single 8 (14.3) 14 (28.0) 49 (50.0) Married 44 (78.6) 34 (68.0) 45 (45.9) Divorced or other 5 (7.1) 2 (4.0) 4 (4.1) Hometown n (%) 78.39 <0.001 Not Hubei province 18 (31.6) 43 (86.0) 92 (93.9) Hubei province 39 (68.4) 7 (14.0) 6 (6.1) Prevalence of Depression n (%) 21 (29.2)c 6 (9.8) 61 (34.7) 8.284 0.016 Prevalence of Anxiety n (%) 15 (20.8) 5 (10.2) 43 (19.6) 3.741 0.154 Depression comorbid with Anxiety n(%) 12 (21.1) 6 (8) 22 (22.4) 4.91 0.086 Severity of depressive symptomsn (%) 20.26 0.002 None 21 (36.8) 35 (70.0) 49 (50.0) Mild 18 (31.6) 10 (20.0) 15 (15.3) Moderate 7 (12.3) 3 (6.0) 20 (20.4) Severe 11 (19.3)d 2 (4.0) 14 (14.3) Severity of anxiety symptomsn (%) 8.86 0.182 None 31 (54.4) 36 (72.0) 60 (61.2) Mild 14 (36.8) 9 (18.0) 15 (15.3) Moderate 4 (26.7) 4 (8.0) * 7 (7.1) Severe 8 (32.0) 1 (2.0) * 16 (16.3) * Expected count less than 5; ** educational level of two respondents were not available a Significant difference between the general public and the other two groups (p value < 0.01); b Significant difference between group analysis with Bonferroni post-hoc analysis (all p values < 0.01); c Statistical significance compared to individuals under quarantine with adjusted p values (Bonferroni method); d Statistical significance compared to individuals under quarantine with adjusted p values (Bonferroni method) To the best of our knowledge, this is the first study aimed at exploring the psychological health across populations with different levels of exposure to the COVID-19 epidemic. Our study revealed differential levels of psychological distress in patients who experienced COVID-19 infection, individuals under quarantine, and the general public. The vulnerability to psychological distress across populations in the COVID-19 pandemic could be attributable to various factors, including gender, social support, specific experiences with COVID-19 infection, length of isolation, and amount of exposure to the media (Brooks et al., 2020, Li et al., 2020). The preliminary findings from our study suggest that timely identification of psychological distress and precise classifying of the mental health needs across populations will facilitate development of targeted psychological interventions for individuals in epidemics of emerging infectious diseases. Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have influence the work reported in this correspondence Uncited references Kang et al., 2019, Health, 2020.