Table 1. Descriptive characteristics of studies investigating the association between the Met allele of the Val158Met polymorphism and violence.

Note: – = data not obtainable; UK = United Kingdom; S Korea = South Korea; Dx = diagnostic system; DSM-IV = Diagnostic and Statistical Manual of Mental Disorders (4th edition); ICD-10 = International Classification of Diseases (10th edition); CCMD-3 = Chinese Classification of Mental Disorders; n = sample size; % Male = percentage of male participants; % Alc = percentage of participants with lifetime diagnoses of alcohol abuse or dependence; % Drug = percentage of participants with lifetime diagnoses of drug (non-alcohol) abuse or dependence. Total sample sizes and the number of participants within each genotype are not always equivalent to those that appear in published articles, as only individuals diagnosed with schizophrenia were included in the present review and outcome data could not always be obtained for all participants.