Interpretation Bias in Paranoia: A Systematic Review and Meta-Analysis

More than 10% of the general population regularly experience paranoid thoughts. Persecutory delusions occur in one third of psychiatric patients in the United Kingdom and are associated with severe clinical and social impairment. Furthermore, individuals with elevated vulnerability to paranoia interpret ambiguous environmental information more negatively than those with low vulnerability, a cognitive phenomenon called interpretation bias. We conducted a systematic review and meta-analysis of the association between interpretation bias and paranoia. Twenty studies were included, and our meta-analysis indicated that a negative interpretation bias was associated with paranoia both in clinical (standardized mean difference, or SMD = 1.01; 95% confidence interval [CI] = [0.51, 1.52], p < .001) and nonclinical populations (SMD = 1.06; 95% CI = [0.28, 1.85], p = .008). Our results also showed that higher negative interpretation bias was positively correlated with the severity of paranoia, and results were consistent in nonclinical (r = .32; 95% CI = [.21, .43], p < .001) and clinical samples (r = .38; 95% CI = [.27, .48], p < .001). These findings might orient prevention strategies and psychological interventions for paranoia.