The pandemic triggered an increase in the incidences of mental health problems across the globe. It also revealed a need to identify what mental health service provision, available at population-level, is effective. A population-level problem naturally requires solutions that can be rolled out at scale. Since January 2022, the EPPI-Centre (UCL), which is part of the the International Public Policy Observatory (IPPO) collaboration, has been conducting a systematic review of the most effective, scalable interventions to address anxiety and depression, shown to have surfaced during the COVID-19 pandemic. The policy briefing that...