Evaluation of variability in individual response to treatments in the clinical high-risk state for psychosis: A meta-analysis

Background: Individuals at Clinical High Risk for Psychosis (CHR-P) may differ considerably in their response to indicated preventive interventions. No studies have tested this. Method: PRISMA-compliant systematic review of the Web of Science (MEDLINE), PsycInfo, CENTRAL and unpublished/gray literature up to 1 September 2019. RCTs in CHR-P individuals, reporting on attenuated positive psychotic symptoms were included. The primary outcome was the variability ratio between the variance of the severity of attenuated positive psychotic symptoms in the indicated intervention condition vs the control condition (needs-based interventions. NBI) at 6 and 12 months. Random effect models, C statistics, meta-regressions/ sensitivity analyses and Cochrane Risk of Bias assessment were performed. Results: Overall, 1707 individuals from 14 RCTs (57% male, mean age = 20) reporting on the impact of preventive interventions on attenuated positive psychotic symptoms were included. At 6 months, the variability ratio was 1 (95% CI 0.89-1.12). At 12 months, the variability ratio was higher in the indicated intervention compared to the NBI condition but not statistically different: 1.09 (95% CI 0.94-125). Between-study heterogeneity was serious (I-2 = 51% and 68%, respectively), but sensitivity analysis suggested it may be related to two outlying studies or larger variability in the response to treatment in small studies. Conclusions: There is no evidence for individual differences in CHR-P response to preventive treatments. Although the study cannot exclude that subsets of CHR-P individuals may respond differently to preventive treatments, it indicates that the average effect of preventive interventions is a reasonable estimate for the CHR-P individual. (C) 2020 Elsevier B.V. All rights reserved.

Automated summary

A systematic review found significant differences in response to indicated preventive interventions among CHR-P individuals, but no evidence for individual differences in response to preventive treatments overall. The variability ratio was higher in the indicated intervention compared to the NBI condition at 12 months, indicating potential differences in response over time. The study suggests that the average effect of preventive interventions may be a reasonable estimate for CHR-P individuals.