Androgen levels and anger and impulsivity measures as predictors of physical, verbal and indirect aggression in boys and girls.

Previous studies indicate that androgen levels and certain psychological characteristics such as anger and impulsivity are related to the development and maintenance of aggression. Further studies are required to analyze the potential predictor role of the interaction of said factors on aggressive behavior. 90 nine-year-old children (44 boys and 46 girls) were assessed in relation to their levels of physical, verbal and indirect aggression, using a peer-rating technique. Testosterone and androstenedione levels were analyzed using an enzymoimmunoassay technique in saliva samples. Anger (state and trait) and anger control were measured using the STAXI-NA, and impulsivity was measured through the MFF-20. A General Linear Model revealed that sex was the best predictor for aggression measures, with boys scoring higher than girls in physical, verbal and indirect aggression; after sex, testosterone was found to be the best predictor (in a positive sense) of all three types of aggressive behavior studied. In addition to observing a main effect of androstenedione on physical and verbal aggression, a 'state anger*androstenedione' interaction was found to predict these types of aggression, with androstenedione acting as a moderator (inhibitor) of the effects of anger on these behaviors; also, a 'state anger*testosterone' interaction was found to predict verbal aggression. The results support the idea that, after sex, androgens constitute a biological marker to be taken into consideration in relation to individual differences in aggressive behavior. It is possible that at the age of 9, testosterone tends to increase aggression, while androstenedione tends to moderate (inhibit) the effects of anger on aggression.