Multiplex families ascertained through multiple alcohol dependent individuals appear to transmit alcohol and drug use disorders at even higher rates than randomly selected families of alcoholics (Hill and Muka, 1996; Hill et al., 1999a), providing an opportunity for identification of neurobiological markers and genetic polymorphisms for disease susceptibility (Morton and Mi, 1968; Smalley et al., 2000; Seidman et al., 2002). Genes contributing to susceptibility for adult onset alcohol dependence may have pleiotropic effects in childhood that increase risk for a broad spectrum of child and adolescent psychopathology. Obtaining a better understanding of this relationship will require uncovering reliable rates of illness in offspring.
