Interaction between MAO-A genotype and maltreatment in the risk for conduct disorder: Failure to confirm in adolescent patients

Objective: Childhood maltreatment is a potent risk factor for subsequent aggressive and criminal behavior. A recent study suggested that the relationship between maltreatment and antisocial behavior may be moderated by a genetic vulnerability conferred by a functional polymorphism in the MAO-A gene. The authors investigated whether these findings would generalize to a clinical cohort of adolescents, examining whether there was a stronger association between maltreatment and conduct disorder severity in patients carrying the low MAO-A activity allele. Method: Male adolescent patients (N = 247) entering residential or intensive day treatment for persistent conduct and substance use problems were examined. Conduct disorder severity was indexed by a lifetime count of DSM-IV criteria obtained through structured psychiatric interviews. Maltreatment scores were derived from summing neglect and abuse events reported to have occurred before age 11. Results: Neglect, verbal/psychological abuse, physical abuse, and sexual abuse were prevalent among patients. Although level of maltreatment and lifetime conduct disorder symptoms were significantly correlated, no genetic-environmental interaction with genotype for maltreatment was found. Conclusion: The results of the current study do not support the hypothesis that a polymorphism in the gene encoding MAO-A contributes to the genetic risk for conduct disorder.