Funding for this research was provided by:
European Research Council (324176)
Received: 28 April 2019
Accepted: 9 October 2019
First Online: 15 November 2019
Ethics approval and consent to participate
: Ethical approval was obtained from the National Health Service (NHS) National Research Ethics Service (NRES), which provided approval to collect genetic material as well as administering psychological measures. The study received ethical approval from the NRES Committee South Central (14/SC/0128) on the 30th September 2014 (Project ID: 141833). Written consent was obtained from parent consent forms and adolescent assent forms for each participant.
: Consent to publish research findings was obtained from parent consent forms and adolescent assent forms, with the explanation that data would be analysed at a group level, which would not identify the identity of any individual participant or school taking part.
: The authors declare that they have no competing interests.