Wiers, C E
Shumay, E
Volkow, N D
Frieling, H
Kotsiari, A
Lindenmeyer, J
Walter, H
Bermpohl, F
Article History
Received: 19 April 2015
Revised: 1 August 2015
Accepted: 5 August 2015
First Online: 29 September 2015
Competing interests
: The authors declare no conflict of interest.