Metaregression analyses examining sources of heterogeneity in studies investigating the association between the Met allele of the Val158Met polymorphism and violence.

Note: SE = standard error; – = analysis not applicable or data not available. Diagnostic odds ratios from the Val/Val vs. Val/Met + Met/Met comparison were used. The moderating role of sample ethnic composition was not investigated due to low levels of within-study ethnic diversity, resulting in overlap with continent of origin. No evidence of significant moderation was found (p >0.05 in all cases).aStudy data on men vs. women.bInstitutional and criminal records.