Article History
Received: 10 May 2017
Revised: 19 September 2017
Accepted: 20 September 2017
First Online: 19 February 2018
Competing interests
: The position of AIL at the University of Oxford is funded by Big Health Ltd, the company behind the digital CBT program evaluated for this manuscript. PFM is employed by Big Health Ltd. CAE is the clinical and scientific director of Big Health Ltd and holds shares in Big Health Ltd.