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PRISMA-compliant systematic review of the Web of Science (MEDLINE), PsycInfo, CENTRAL and unpublished/gray literature up to 1 September 2019.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 0.94-1.25). Between-study heterogeneity was serious (I = 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.