The subjects of the study completed the questionnaire from September 8 to 29 2020. The subjects consisted of those who were either hospitalized or outpatients at Yongin Mental Hospital during the same period, and patients diagnosed with schizophrenia by the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) were targeted. Among them, participants were limited to adults over the age of 19 and those who could understand and participate in the study by reading consent forms and questionnaires by themselves. To compare the patients’ perceptions about COVID-19 to those of the general public, a questionnaire was completed by and received from 40 medical and administrative staff who worked at Yongin Mental Hospital and did not have a psychiatric history. The purpose and method of the study were fully explained to all study participants, and written consent was obtained. This study was approved by the Yongin Mental Hospital Institutional Review Board (YIMH-IRB 2020-20, the date of ethics committee approval; September 2, 2020).

The research subjects were given self-report questionnaires and asked to answer questions regarding their personal information (age, gender, education). Basic knowledge, such as the current status of COVID-19 in Korea and changes made to their daily life due to COVID-19, as well as questions regarding the number of cumulative confirmed cases, the probability of death, the infection route of SARS-CoV-2, methods for preventing infection, and main symptoms of COVID-19 were confirmed through a self-report questionnaire developed by the authors. The contents of the survey were referenced in a study of the general population [14], and each question was presented simply and clearly in one sentence so that schizophrenia patients could easily understand it.

The questionnaires consisted of a total of 10 items. One item asked about changes experienced in the respondents’ daily lives. Three items presented multiple choice questions about the current status of COVID-19 (the cumulative number of confirmed cases and the mortality rate) to test the respondents’ knowledge about COVID-19, the actions to prevent infection (multiple responses), the main paths of infection, and the main symptoms (multiple responses) of the disease. One item consisting of 8 sentences was answered with yes or no. This confirmed the respondents’ misconceptions about COVID-19.

Cronbach’s alpha reliability coefficient was 0.66, which was considered satisfactory for this study.

In addition, an item asked the patients where they obtained their information about COVID-19 (multiple responses). Finally, the Fear of COVID-19 Scale (hereinafter FC-19s) [15] was included in the questionnaire to assess the respondents’ degree of fear of COVID-19. The section on the FC-19s required the respondents to answer 7 questions using a Likert-type scale ranging from 1 to 5; the higher the overall score was, the higher the respondent’s degree of fear.

Through computerized medical records, the subject’s age, education, and diagnosis were reconfirmed. The patient’s psychopathology was directly determined by a psychiatrist and was measured using the Clinical Global Impressions Scale Severity Score (CGI-S) and the Global Assessment Functioning Scale (GAF).

Descriptive statistics (mean, standard deviation [SD]) were computed for demographic variables. The years of education among the three groups were analyzed by ANOVA, and post hoc analysis (Scheffe) was performed. Student’s t test was performed on each group to compare the differences between the mean values of the CGI-S, GAF, and FC-19. Categorical variables such as sex, changes in daily life, and knowledge about COVID-19 were compared with the χ2 test. The percentage of participants who selected each response was computed. Descriptive statistics were analyzed using SPSS 22 edition for Windows (IBM SPSS Statistics 22; IBM Corp., Armonk, NY, USA). For all statistical analyses, a value of p<0.05 was considered statistically significant.

A total of 278 patients diagnosed with schizophrenia (161 inpatients, 117 outpatients) and 40 nonpatients were recruited. The participants’ gender distributions showed that there were 65 male (40.4%) inpatients, 50 male (42.7%) outpatients, and 13 males (32.5%) in the nonpatient group. There were no significant differences between these groups. The average age was 54.8 years for inpatients, 47.2 years for outpatients, and 46.3 years for the normal control group. The average number of years of education was 10.9 years for the inpatients, 12.8 years for the outpatients, and 15.8 years for the nonpatient group, which indicated a significant difference between the three groups. The average CGI-S score for psychological symptoms was 4.8 for inpatients and 3.6 for outpatients, and the average GAF score was 44.1 points for inpatients and 55.5 points for outpatients. Both evaluation scales showed no significant differences between the two groups (Table 1).

When asked if there had been any change in their lives due to COVID-19, among the inpatients, 51.6% answered positively, followed by 65.5% of the outpatients and 85.0% of the nonpatient respondents (Fig. 1). In the nonpatient group, 77.5% of the respondents reported a decrease in their level of activity, and 30% reported a decrease in their mood. In the schizophrenic patient group, decreased activity levels, decreased mood, decreased appetite, and poor sleep were reported (Fig. 1).

Other responses from patients with schizophrenia reported that among the inpatients, 6 had decreased their walking time, 3 had difficulty going out and staying out, and 6 had difficulty taking walks or going to the store. Others also reported discomfort due to frequent body temperature checks and hand washing and exhibited signs of nervousness and anxiousness. Outpatients complained about the difficulties related to wearing masks, decreased income, and not being able to use saunas and swimming pools.

To date, compared to the 69.2% of the nonpatient respondents who answered that the cumulative number of confirmed COVID-19 cases was between 10,001 and 100,000, only 25.3% of the inpatients and 41.4% of the outpatients were aware of this correct answer (Fig. 2). A total of 15.4% of the nonpatient group, 55.4% of the inpatients and 46.5% of the outpatients answered that the cumulative number of confirmed cases was 10,000 or less. The cumulative number of COVID-19 cases was perceived to be lower in the order of inpatients, outpatients and normal controls (The cumulative number of confirmed patients was 10,001 and 100,000 at the time of the survey).

None of the normal controls thought that the mortality rate would be less than 5%, while 45% of inpatients and 63% of outpatients responded that the mortality rate from COVID-19 was less than 5% (Fig. 3). Seventy-five percent of normal controls, 62% of outpatients and 57% of inpatients responded that the mortality rate of the common cold was less than 1% (Fig. 4). The mortality rates of COVID-19 and the common cold were higher in the order of inpatients, outpatients and normal controls (The mortality rate from COVID-19 in Koreas was less than 5% at the time of the survey).

Regarding the main route of SARS-CoV-2 infection, all of the normal controls except for the nonresponders selected that the disease was transmitted ‘by contaminated saliva,’ whereas various routes of infection were selected by patients with schizophrenia (Fig. 5). The most common option selected by these patients was ‘contaminated saliva’ (inpatient 41.6%, outpatient 82.9%), while other answers consisted of ‘contaminated food’ (inpatient 18.6%, outpatient 9.4%) or ‘mosquito bites’ (inpatient 13.7%). Various other options were also selected (Fig. 5).

Next, for the main symptoms of COVID-19, cough and fever were selected by 95% of normal controls and more than 80% of the outpatients (Fig. 6). In the case of inpatients, symptoms such as cough (74.5%), fever (65.2%), shortness of breath (58.4%), skin rash (29.8%), constipation (25.5%), and dysuria (20.5%) were chosen (Fig. 6).

For preventive measures regarding the transmission of COVID-19, almost all normal controls and outpatients selected items such as ‘wearing a medical mask,’ ’washing hands,’ and ‘avoiding touching your eyes, nose and mouth with unclean hands.’ The answers ‘avoiding people with fever’ and ‘gargling mouthwash’ were also selected at a high rate (Fig. 7). However, the inpatients with schizophrenia were all items, which were ‘wearing a medical mask,’ ‘avoiding touching the eyes, nose and mouth with unclean hands,’ and ‘avoiding people with fever’ and ‘gargling mouthwash,’ also selected other measures such as ‘getting a pneumonia shot,’ ’eating garlic,’ ’taking antibiotics,’ ‘consuming alcohol-based disinfectant,’ and ‘rinsing nasal cavity with saline’ (Fig. 7).

When asked about whether “the most effective way to prevent COVID-19 infection is to wash your hands and wear a mask,” more than 90% of all groups recognized this as the correct answer (Fig. 8). However, 25% of the inpatients and 5% of the outpatients thought that ‘young people cannot get infected with SARS-CoV-2.’ In addition, 46.9% of the inpatients and 11.3% of the outpatients said that ‘there are currently vaccinations and treatments against COVID-19’ (Fig. 8). (There was no vaccine or treatment at the time of the survey.) Approximately 60%-70% of the patients with schizophrenia were aware that ‘the death rate from COVID-19 increases when there is another underlying disease.’ In addition, 56.3% of the inpatients, 27.8% of the outpatients, and 7.7% of the non-patients answered incorrectly to ‘you should use public transportation to go to the hospital if you have a fever or cough after going to church’ (Fig. 8). In addition, 53.8% of the inpatients and 36.5% of the outpatients thought that if they received a letter or package from China, they were more likely to contract COVID-19 (Fig. 8). A total of 31.3% of the inpatients, 15.7% of the outpatients, and 7.7% of the nonpatients answered that it is certain that COVID-19 was deliberately created by and spread from China (Fig. 8).

More than 80% of the patients with schizophrenia responded that their information related to the virus was obtained through TV, while 97.5% of the nonpatient group collected information through the internet (Fig. 9). Other channels of information included radio (56.9%), medical staff (40.0%), and newspapers (23.8%) for inpatients; outpatients reported using the internet (48.8%), family (29.9%), and the radio (27.6%) as their sources of information (Fig. 9).

The average scores on the Fear of COVID-19 Scale were 19.7 points for inpatients, 19.0 points for outpatients, and 16.0 points for nonpatients. Compared to the nonpatient group, inpatients and outpatients had a higher degree of subjective fear of COVID-19 (Table 1).