The COVID-19 pandemic had a major impact on the field of psychiatry. Nagasaki Medical Center of Psychiatry plays a central role in psychiatric emergency care in the prefecture. We compared the treatment results in our hospital in the two years before and after the pandemic. After the pandemic, out-of-hours medical care decreased, and compulsory hospitalization increased compared with before the pandemic. There was no marked decrease in compulsory hospitalization to other hospitals, and compulsory hospitalization in Nagasaki Prefecture on the whole was on the rise. Due to the COVID-19 pandemic, early intervention in cases of exacerbation of the mental condition might become more difficult, and patients might be more likely to develop a severe condition and therefore need to be urgently hospitalized.