A longitudinal study of depression differ depending on age during COVID-19 infection

We conducted a longitudinal survey which consisted of 3 times web-based surveys with an online research company, Macromill, Inc. Japan. The first survey was conducted from 17 to 22 July 2020 for participants who are 20 to 69 years old, lived in the prefectures under special precautions that were related to the COVID-19 pandemic: Tokyo, Saitama, Chiba, Kanagawa, Osaka, Hyogo, Fukuoka, Hokkaido, Ibaraki, Ishikawa, Gifu, Aichi, and Kyoto. And a quota sampling method was used to compare equal-sized age groups (20s, 30s, 40s, 50s, 60s, and 70s), sex (male and female), and employment status (full-time worker; no regular employment; and unemployed, including homemaker, retired, and jobless). Second survey was conducted from 18 to 23 September 2020 and third survey was conducted from 22 to 27 January 2021 for participants who answered the 1st survey. The web-survey questionnaire contained demographic information, economic impact of the COVID-19 pandemic, the Patient Health Questionnaire-9 (PHQ-9), anger, and coping strategy scale. At the time 1 survey, 2,708 participants answered.