. 2019 Oct 7;5(6):e88. doi: 10.1192/bjo.2019.71
© The Authors 2019
This is an Open Access article, distributed under the terms of the Creative Commons Attribution licence (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted re-use, distribution, and reproduction in any medium, provided the original work is properly cited.