More than half of a sample of US COVID-19 survivors reported symptoms of major depressive disorder months after recovery, a research letter today in JAMA Network Open reports.A team led by researchers from Massachusetts General Hospital and Harvard University analyzed internet-based nonprobability survey and Patient Health Questionnaire-9 (PHQ-9) responses from 82,319 adult coronavirus survivors delivered in eight waves from June 2020 to January 2021.The PHQ-9 is a nine-question depression screening tool with 0 to 27 possible points; 10 or more points indicate moderate depression.Headache, severity of coronavirus symptomsOf all respondents, 3,904 reported a previous coronavirus infection.