“…1; Bernal, Cummins, & Gasparrini, 2017 , 2020 ; Bhaskaran, Gasparrini, Hajat, Smeeth, & Armstrong, 2013 ), a quasi-experimental study design (Shadish, Cook, & Campbell, 2002 ), widely used in COVID-19 suicide research (Leske et al, 2021 ; Pirkis et al, 2021 ), to compare monthly incident suicide attempt rates before and during the COVID-19 pandemic. Data collection covered the period from 1 January 2013 to 1 February 2021, thus included three waves of severe restrictions and extended existing studies of the first wave (Anzai, Fukui, Ito, Ito, & Takahashi, 2021 ; Calderon-Anyosa & Kaufman, 2021 ; Vandoros et al, 2020 ). The ITS study design used electronic health registry data that are continuously collected over time.…”