Relação entre genética, ambiente e comportamentos externalizantes em adolescentes de Belo Horizonte

Abstract

Externalizing behaviors include manifestations of aggression, hyperactivity, impulsivity, opposition, defiance, and antisocial behavior. The occurrence of these behavioral problems in the population is 5%, and they are more frequent and manifest with greater severity in males. Among the genes associated with aggressive behavior, the monoamine oxidase A gene stands out, where low-activity alleles have been associated with an increased risk of developing aggressive behavior. Research indicates that the occurrence of mistreatment and negative stressful events in childhood lead to a differentiation in aggressive responses. The present study aims to verify the relationship between genetic and environmental variables in the manifestation of aggressive behavior in adolescents. The sample consisted of 300 male students, aged between 15 and 17 years. The schools selected based on the average score in the National High School Exam (ENEM), with two high-performance (AD) and four low-performance (BD). The instruments used for psychological measurements: Childhood Trauma Questionnaire (QUESI), Attention Deficit Hyperactivity Disorder Scale; Five-Factor Personality Inventory (NEO FFI-R); Raven's Progressive Matrices – General Scale; Brazilian Economic Classification Criteria (Critério Brasil) and an adapted version of the PISA test. The enzymatic activity of MAO-A was inferred by genotyping of MAOA-uVNTR, based on PCR amplification and Fragment Analysis by Capillary Electrophoresis. According to the number of copies of the MAOA-uVNTR repeat monomer, the alleles classified as low activity (2R and 3R) or high activity (3.5R and 4R). As a result, the 3R and 4R polymorphisms were the most prevalent, comprising 91% of the total frequency. In the relationships between environmental, psychological and genetic variables, it observed that only physical abuse presented a significant association with allelic activity, that is, a tendency for the group of low-activity individuals to present a higher level of physical abuse. However, no global linear regression model reached statistical significance and, therefore, no evidence obtained for a moderating effect. Keywords: School Context; Externalizing Behaviors; Aggression; MAOA u-VNTR