Participants and recruitment
low mood, depressed, Depressive
Participants were recruited primarily online, e.g. via social media posts and paid adverts, with adverts indicating that the study involved an online training program that could help with depressed or low mood (see online Supplementary Methods for details). Adverts directed participants to the study website, where they could provide informed consent and register for the study.Inclusion criteria were: Aged ≥ 18; scoring ≥ 6 on the Quick Inventory of Depressive Symptomatology (QIDS; Rush et al., The study was conducted entirely online. Study procedures (assessments, interventions, participant tracking) were implemented via a web-based platform and were entirely automated and unguided, with contact from researchers only in response to queries from the participants or to provide technical information (e.g. website unavailability).