Funding for this research was provided by:
Medical Research Council (74882)
Wellcome Trust (076467)
National Institute on Drug Abuse (K01DA034753)
Maternal and Child Health Bureau (6T71-MC0009, MC00001)
National Institute for Health Research (DHCS/08/08/012)
Article History
Received: 26 October 2017
Accepted: 13 March 2018
First Online: 17 March 2018
Compliance with ethical standards
:
: On behalf of all authors, the corresponding author states that there are no conflicts of interest.