The present study should be considered in light of several limitations. First, the clinical interview did not assess the number of occasions of maltreatment or the identity of the perpetrator. Therefore, the current study is limited in its ability to determine the importance of these aspects of maltreatment on alcoholism risk. In addition, we do not have measures of childhood maltreatment reliability and validity. However, previous studies indicate that retrospective acknowledgement of adverse childhood experiences is generally reliable and valid (Brewin et al. 1993). Our definition of childhood maltreatment includes parent–child maltreatment, which could be a reaction to the child's behavior. It is possible that adolescent externalizing behaviors lead to harsh parenting and problematic alcohol use, rather than childhood maltreatment leading to alcoholism. Given the low prevalence of sexual abuse and neglect, we have insufficient power to conduct twin analyses separately for each type of maltreatment. Future studies should examine whether the mechanisms that underlie the maltreatment–alcoholism association differ for specific forms of childhood maltreatment. Our investigation of mediating variables was exploratory and other mechanisms are also possible.
