Checknita, David http://orcid.org/0000-0002-7005-2565
Ekström, Tomas J.
Comasco, Erika
Nilsson, Kent W.
Tiihonen, Jari
Hodgins, Sheilagh
Funding for this research was provided by:
Swedish Council for Working Life and Social Research
Mobilsering mot Narkotika
County Council of Stockholm
County Council of Västmanland
Karolinska Institutet Strategic Funding
Article History
Received: 1 November 2017
Accepted: 8 March 2018
First Online: 29 March 2018
Compliance with ethical standards
:
: The authors report no biomedical financial interests or potential conflicts of interest.
: All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards. All waves of data collection were approved by the Regional Ethical Review Board in Stockholm. At each wave of data collection, participants signed informed consents, except at baseline when consent for those under age 18 was given by their parents. At collection of saliva samples all participants were 18 or older, and they specifically consented to providing saliva samples for DNA extraction. Confidentiality of all the information was guaranteed, and, at each wave of data collection, participants received gift certificates as compensation for their time.