The use of populations not ascertained for illness behavior, such as the Iowa Adoption Studies (IAS), could help decipher the interrelationships of these disorders. The IAS, founded by the late Remi Cadoret in the 1970’s, are a case and control adoption study that compare and contrast data from adoptees at high biological risk for substance use and ASPD (i.e. whose parents had severe substance use or ASPD) with that from adoptees at low biological risk for behavioral illness (i.e. whose parents had no history of behavioral illness). Because these adoptees were randomized into adoptive environments and ascertained because of their adoptive status, not their behavioral status, examination of behavioral outcomes in the IAS is not confounded by method of ascertainment. Therefore, although the IAS is not a general population sample, it is an epidemiologically sound and useful paradigm through which to explore the effect of genetic, environmental and gene environment interactions on human behavior.
