has also been observed in numerous subsequent studies across general population, collegiate and treatment samples. 25 , 26 , 27 In another COGA study, analysis of the early family data led to observations of both common and specific evidence for familial transmission of alcohol, marijuana, and cocaine dependence and habitual smoking, 28 a finding confirmed in later COGA investigations, 29 as well as in a number of independent twin‐family samples analyzed by other researchers. 30 , 31 In another later analysis of the completed Wave 1 data collected on over 9000 probands, their relatives, and comparison participants, we reported a two‐fold excess risk for AUD in relatives of probands with AUD, and observed strong co‐aggregation with antisocial personality disorder, other drug dependence, and anxiety and mood disorders. 3 Similar co‐aggregation of AUD and other externalizing disorders has been documented in independent twin‐family data by other researchers. 32 COGA also found that the presence of a physiological dependence component to alcohol and other substance use disorders implicated a more severe clinical course, that held for alcohol as well as other substances. 33 Other analyses investigated evidence in COGA of a previously established AUD subtype, Type A‐B clusters, 34 finding that among
