Public health primary prevention implemented by clinical high-risk services for psychosis.

Clinical High Risk for Psychosis (CHR-P) services have been primarily developed to support young people with attenuated symptoms (indicated prevention). No evidence-based appraisal has systematically investigated to what extent these clinics may implement other preventive approaches. PRISMA 2020-compliant systematic review of Web of Science, Cochrane Central Register of Reviews, and Ovid/PsychINFO, from inception until 14th June 2021, identifying original studies describing public health strategies: (a) service characteristics (configuration of mental health service, outreach, pathways to care); (b) universal interventions (general population); (c) selective interventions targeting CHR-P service-users or family/carers. Public health preventive initiatives were systematically stratified according to core social determinants of mental disorders associated with the 2030 Sustainable Development Goals promoted by the United Nations Member States (UN 2030 SDG) and good mental health outcomes. A total of 66 publications were included, providing data on 13 standalone, 40 integrated, three networks, and six regional or international surveys of CHR-P services across Europe, Asia, Oceania, Africa, North and South America, providing care to >28 M people. CHR-P services implement numerous public health initiatives targeting social and cultural (16 initiatives), economic (seven initiatives), demographic (six initiatives), environmental events (four initiatives) and neighbourhood (three initiatives) UN 2030 SGD determinants of mental disorders. There is additional evidence for CHR-P services promoting good mental health. The main barriers were the lack of resources for expanding public health prevention at a large scale. CHR-P services implement numerous public health prevention initiatives and promotion of good mental health beyond indicated prevention of psychosis.