Third, these studies utilized two different methods of assessment. A number of the twin and adoption studies utilized personal interviews, an approach that requires cooperation and relies critically on the accuracy of retrospective reporting of symptoms generally seen as socially undesirable (e.g. Cadoret et al. 1987; Reed et al. 1996; Prescott et al. 1999; True et al. 1999). Other studies utilized registry information, particularly from medical (Reed et al. 1996) and temperance board records (Cloninger et al. 1981; Kendler et al. 1997). This approach typically provides contemporaneously recorded information and requires no cooperation, but might have limited sensitivity and specificity in the detection of AUD as they require affected individuals to be detected with alcohol-related problems by the medical or legal system. While both official registrations – typically from medical and/or legal records – and clinical diagnoses are commonly used assessments of AUD, it is possible that the cases diagnosed by different assessment methods could reflect partly independent latent genetic factors. If the reliability of AUD diagnoses differed with these two methods, it could be reflected in additive genetic, shared
