The host trial was a randomised controlled trial of a digital intervention for paranoia (STOP; Successful Treatment of Paranoia). People who were referred to the host trial and opted to receive an online version of the Participant Information Sheet were eligible for enrolment into the SWAT. Before accessing the online Participant Information Sheet, people were randomly allocated to watch either a brief online video with patient testimonies about taking part in physical health research (general), mental health research (tailored to topic of host trial), or a no video control. We collected data on who expressed interest in taking part, and who went on to be randomised into the trial in each condition.