Détection et intervention précoce pour la psychose : pourquoi et comment ?

Objectives This article aims to synthesize the critical stages in the development of early detection and intervention services (EIS) for psychosis over the past 30 years, and to review key literature on the essential components and effectiveness of these programs. Method We conducted a narrative review of the literature on the international development of EIS leading to its endorsement as a service delivery model for young people with first­episode psychosis (FEP). We also reviewed various inter­ national and Canadian guidelines to identify consensus about the essential compo­ nents of EIS for psychosis and their effectiveness. Challenges to the implementation of these different essential components are presented, along with practical solu­ tions to addressing them. A particular emphasis is placed on implementing EIS in the Quebec context. Results Based on a model developed in the early 1990s, EIS for psychosis have now been disseminated worldwide and are deployed on a large scale in some regions, such as the United Kingdom and Quebec. The model’s gradual expansion has been facilitated by efforts to identify its main objectives and the components essential to achieve them, and by several studies demonstrating its effectiveness. Along with an important philosophical shift to optimism and hope, EIS have typically focused on the twin aims of reducing treatment delay (or the duration of untreated psychosis) and enhancing engagement in specialized, phase­specific, developmentally appropriate treatment. A meta­analysis (published in 2018) demonstrated the superiority of EIS for psychosis compared to standard treatment on several outcomes including hospitalizations, relapse of symptoms, treatment discontinuation, and vocational and social functioning. Based on these studies and expert consensus, many jurisdictions around the world have developed guidelines to ensure compliance with essential components that are associated with the effec­ tiveness of EIS, while accounting for their