Davies, G
Marioni, R E
Liewald, D C
Hill, W D
Hagenaars, S P
Harris, S E
Ritchie, S J
Luciano, M
Fawns-Ritchie, C
Lyall, D
Cullen, B
Cox, S R
Hayward, C
Porteous, D J
Evans, J
McIntosh, A M
Gallacher, J
Craddock, N
Pell, J P
Smith, D J
Gale, C R
Deary, I J
Article History
Received: 24 August 2015
Revised: 14 January 2016
Accepted: 11 February 2016
First Online: 5 April 2016
Competing interests
: The authors declare no conflict of interest.