King's College London

Background: Early-onset psychosis (EOP) refers to the development of a first episode of psychosis before 18 years. Individuals at clinical high-risk for psychosis (CHR-P) include adolescents and young adults, although most evidence has focused on adults. Negative symptoms are important prognostic indicators for patients with psychosis. However, research focusing on children and adolescents (C&A) is limited.
Aims: Provide meta-analytical evidence and a comprehensive review of the status and advances in the diagnosis, prognosis and treatment of negative symptoms in C&A with EOP&CHR-P.

Method: PRISMA/MOOSE-compliant systematic review (PROSPERO:CRD42022360925) from inception through 18-08-2022, in any language, to identify individual studies conducted in EOP/CHR-P C&A (mean age
Results: Of 3,289 articles, 133 were included (n=6,776 EOP, mean age=15.3±1.6 years, males=56.1%; n=2,138 CHR-P, mean age=16.1±1.0 years, males=48.6%). There were negative symptoms in 60.8% (95%CI=46.4%–75.2%) of C&A with EOP and 79.6% (95%CI=66.3%–92.9%) of C&A at CHR-P. Prevalence and severity of negative symptoms were associated with poor clinical, functional and intervention outcomes in the included studies on CHR-P&EOP. Different interventions were piloted with variable results requiring further replication.

Conclusions: Negative symptoms are common in C&A at early stages of psychosis, particularly in those at CHR-P, and associated with poor outcomes. Future intervention research is required so that evidence-based treatments will become available for C&A.