Participants
A national community sample of people in the UK who had previously self-harmed were recruited via a survey panel company (YouGov), as part of a larger study (ClinicalTrials.gov Identifier: NCT04420546). Participants were incentivised in line with YouGov’s points system (respondents accumulate points for taking part in surveys, which can then be exchanged for cash or entry into a prize draw). A screening question was asked to ensure that the final sample contained people with a prior history of self-harm: “Have you ever intentionally hurt yourself/self-harmed?” Response options were “yes, I have,” “no, I have not,” or “prefer not to say.” The final sample was based on respondents answering, “yes, I have.”