Background: In response to the coronavirus disease 2019 (COVID-19) pandemic, Singapore raised its Disease Outbreak Response System Condition alert to “orange,” the second highest level. Between 19 February and 13 March 2020, confirmed cases rose from 84 to 200 (34.2 per 1 000 000 population), with an increase in patients in critical condition from 4 to 11 (5.5%) and no reported deaths in Singapore (1). Understanding the psychological impact of the COVID-19 outbreak among health care workers is crucial in guiding policies and interventions to maintain their psychological well-being.

Objective: To examine the psychological distress, depression, anxiety, and stress experienced by health care workers in Singapore in the midst of the outbreak, and to compare these between medically and non–medically trained hospital personnel.

Methods and Findings: From 19 February to 13 March 2020, health care workers from 2 major tertiary institutions in Singapore who were caring for patients with COVID-19 were invited to participate with a self-administered questionnaire. In addition to information on demographic characteristics and medical history (Table 1), the questionnaire included the validated Depression, Anxiety, and Stress Scales (DASS-21) and the Impact of Events Scale–Revised (IES-R) instrument (2, 3). Health care workers included “medical”(physicians, nurses) and “nonmedical” personnel (allied health professionals, pharmacists, technicians, administrators, clerical staff, and maintenance workers). The primary outcome was the prevalence of depression, stress, anxiety, and posttraumatic stress disorder (PTSD) among all health care workers (Table 2). Secondary outcomes were comparison of the prevalence of depression, anxiety, stress, and PTSD, and mean DASS-21 and IES-R scores between medical and nonmedical health care workers. The Pearson χ 2 test and student t test were used to compare categorical and continuous outcomes, respectively, between the 2 groups. Multivariable regression was used to adjust for the a priori defined confounders of age, sex, ethnicity, marital status, presence of comorbid conditions, and survey completion date.