in females, the large majority (75–92 %) of genetic risk factors were shared with the other externalizing disorders (Table 7). The exception was CB in females where over half of the total heritability derived from syndrome-specific genetic risk factors. Fifth, the pattern was quite different for shared environmental risk factors. For DA and CB in males, roughly half of the shared environmental influences were shared with the latent construct of externalizing disorders and half were specific to these syndromes. However, for AUD in males, and DA and CB in females, nearly all of the shared environmental influences were shared with other externalizing disorders. Finally, for AUD in females, nearly 90 % of the shared environmental effects were unique to that syndrome. Finally, a higher proportion of the unique environmental effects for DA in both males and females were shared in common with the other disorders than was seen for CB and AUD.
