Selective processing in attention and memory in schizophrenia: A meta-analysis of the negative priming effect

Individuals with schizophrenia show impairments in a variety of selective attention tasks. Research on the negative priming (NP) effect in schizophrenia has yielded mixed evidence. This meta-analysis aimed to examine the NP effect exhibited by patients with schizophrenia and the impact of study methodology on findings. The methods and reporting of this meta-analysis followed the PRISMA guideline. Eligible studies were identified through primary literature search in MEDLINE, PsycInfo, PsycArticles, and Embase and secondary search based on included studies and important reviews. Three-level random effects-models were used to summarize between-group differences in the raw NP score, as well as the NP ratio and baseline reaction time (RT) as secondary outcomes. We identified 1383 studies published between 1966 and 2022 and reviewed 27 studies that consist of 627 patients with schizophrenia and 653 controls in total. Compared to healthy controls, patients with schizophrenia showed a mildly reduced raw NP score with marginal significance, Hedges' g = -0.16, 95% confidence interval (CI) -0.35 to 0.02, p = 0.084. However, analysis of a subsample of studies indicated a significant, moderate reduction in the NP ratio among patients, g = -0.52, 95% CI -0.91 to -0.14; p = 0.014. Moderator analyses revealed a longer illness duration as predictive of a more reduced NP effect. This meta-analysis lends tentative evidence to impaired attention or memory process as measured by the NP task in schizophrenia. More research is needed to substantiate our results and clarify the impact of study design and patient characteristics on findings.