Funding for this research was provided by:
Japan Cancer Society
Japanese Ministry of Health Labor and Welfare (19EA1012)
Received: 13 January 2020
Accepted: 9 December 2020
First Online: 5 January 2021
Ethics approval and consent to participate
: Potential participants first read introductory statements that summarized the contents of the questionnaire and explained they could withdraw at any time if they wished so. Responses were considered consent to participate. Those who were 16–19 years old were asked to confirm the consent of their parents. This study was approved by the Institutional Review Board and Ethics Committee of the National Center for Neurology and Psychiatry, Japan, and was conducted in accordance with the principles laid down in the Helsinki Declaration.
: Not applicable.
: The authors declare that they have no competing interests.