Genetic studies of complex diseases often have advantages when they are conducted in well-defined populations such as Native American tribes living on reservations (Lander and Schork, 1994). The present report is part of a larger study exploring risk factors for substance dependence among Native American Indians (Ehlers et al., 1998, 1999, 2001, 2004a,b, 2006; Garcia-Andrade et al., 1997; Wall et al., 1997, 2003). The lifetime prevalence of substance dependence in this Indian population is high and evidence for heritability and linkage to specific chromosome locations has been demonstrated (Ehlers and Wilhelmsen 2005, 2006, 2007; Ehlers et al., 2004b; Wilhelmsen and Ehlers, 2005). The purpose of the present set of analyses was to explore the comorbidity of alcohol dependence and other externalizing disorders as well as to identify genetic loci associated with antisocial personality disorder/conduct disorder (ASPD/CD). To accomplish these aims autosomal linkage analysis of data from American Indian families was performed. These data are also discussed in the context of previously published data demonstrating linkage to alcohol and other substance related phenotypes in this population (Ehlers et al., 2004b).
