Funding for this research was provided by:
National Institute on Drug Abuse (DA036017, DA027827)
Text and Data Mining valid from 2018-09-03
Received: 8 August 2018
Accepted: 21 August 2018
First Online: 3 September 2018
Compliance with Ethical Standards
: The authors declare that they have no conflict 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.
: Informed consent was obtained from all individual participants included in the study.