hazardous use, 59 and the development of problems. 42 Measures of the intensity of response to alcohol are additional early indicators of genetic risk for alcohol problems, and include both a low level of response seen at peak and falling blood alcohol levels and higher stimulation observed at rising blood levels. 60 , 61 , 62 , 63 Beginning in 1989, longitudinal studies in COGA focused on the low response across several generations of participants. 61 , 64 Not only do impulsivity and low level of response to alcohol directly influence risk, they also appear to indirectly amplify risk via environmental pathways and attitudes, through the selection of riskier peers, positive alcohol expectancies, and increased drinking to cope with stress. 64 , 65 , 66 Additional insights into the factors that underlie the transitions in alcohol involvement from use to disorder have been provided by COGA's collection of electrophysiological indicators of brain function across development, as discussed in greater detail in the companion article in this volume (see 3. Brain function).
