Supporting the in vivo functional impact of this locus. MAOA-LPR was found to predict serotonin 1A receptor availability.124 In a longitudinally studied cohort of boys, Caspi and colleagues125 found an interactive effect between MAOA-LPR and childhood adversity on vulnerability to develop conduct disorder, an important risk factor for addiction. In this study, maltreated boys carrying the MAOA low-activity genotype were more likely to develop antisocial problems than boys with the high-activity genotype. This result has been confirmed by a meta-analysis of eight independent studies.126 Results testing for MAOA × childhood adversity interaction in women are mixed. A recent study conducted in a sample of Native American women with extremely high rates of antisocial personality disorder and exposure to childhood adversity has reported results that parallel those observed in men. In this study, the effect of childhood sexual abuse on risk of developing alcoholism and antisocial personality disorder was influenced by MAOA-LPR genotype.40 Sexually abused women homozygous for the low-activity MAOA-LPR allele had high rates of both disorders, and heterozygous women displayed an intermediate risk pattern. However, in the absence of childhood sexual abuse, there was no relationship between MAOA genotype and these disorders.
