Early Intervention in Psychosis and the Limits of Clinical Paradigms: Long-Term Clinical, Functional, and Social Trajectories in Schizophrenia — A Systematic Review and Integrative Evidence Synthesis

Background: Early intervention in psychosis (EIP) has become a central paradigm in contemporary psychiatry, based on the premise that timely and stage-specific interventions can modify the trajectory of schizophrenia and related psychotic disorders. While substantial evidence supports short-term clinical benefits, the durability and underlying mechanisms of long-term outcomes remain theoretically contested and empirically fragmented. Objective: To critically synthesise evidence on long-term clinical, functional, and social outcomes associated with early intervention in psychosis, integrating biomedical, psychosocial, and structural perspectives within a multidimensional analytical framework. Methods: A systematic review was conducted in accordance with PRISMA 2020 guidelines. PubMed, Web of Science, and SciELO were searched for studies published between January 2013 and December 2023. Eligible studies included randomised controlled trials, prospective cohort studies, and longitudinal observational studies with a minimum follow-up of five years. Methodological quality was assessed using the Cochrane Risk of Bias tool (RoB 2) and the Newcastle–Ottawa Scale. Evidence was synthesised through structured narrative and integrative thematic analysis across clinical, functional, and social domains. Results: Fifteen studies met inclusion criteria. Early intervention was consistently associated with improved short- and medium-term clinical and functional outcomes compared with treatment as usual, including reductions in relapse rates and hospitalisations and improvements in occupational and social functioning. However, the magnitude and persistence of these effects varied substantially across contexts and frequently attenuated over extended follow-up periods. Multidisciplinary interventions integrating pharmacological, psychological, and psychosocial components were associated with more stable long-term trajectories than predominantly biomedical approaches. Structural barriers, service discontinuities, and contextual determinants emerged as recurrent constraints on sustained recovery. Conclusions: Early intervention in psychosis yields meaningful early benefits but does not uniformly translate into durable long-term recovery. These findings challenge reductionist biomedical models of early intervention and support a reconceptualisation of EIP as a multidimensional and systemic process shaped by clinical, psychosocial, and structural determinants. Future research should prioritise longitudinal, multidimensional outcome frameworks and elucidate the mechanisms through which early intervention interacts with contextual factors to shape psychosis trajectories.