Clinical depression, a serious mood disorder that causes persistent feelings of sadness and detachment, is one of the most common mental disorders in the United States, affecting more than 11 million Americans a year, according to the National Institute of Mental Health.

More sleep at night, fewer or no sleep problems, and low levels of professional burnout were associated with a lower risk of developing COVID-19 among healthcare workers considered to be at high risk for exposure to patients with COVID-19, new evidence reveals.