Children who are bright in first grade are more likely touse socially "acceptable" drugs -- including alcohol and marijuana -- in high school than are their slower classmates, a sociology study suggests. The study also found that aggressive first-grade boys are more likely to use such drugs in high school than are other boys, said Margaret Ensminger, a sociologist at the Illinois Institute of Technology in Chicago. The traits that help children be judged bright in first-grade readiness tests may account for their tendency toward using drug substances when they are teenagers, said Ensminger, who worked extensively on the study. These traits include a willingness to take risks and an interest in impressing their peer group. In 1966-67, first-graders in the Woodlawn community of Chicago were evaluated in the study, which was directed by Dr. Sheppard G. Kellam, a University of Chicago psychiatry professor. Some 700 of the first-grade students were interviewed 12 years later. "There is an important sex difference," Ensminger noted. "Girls have more sources of identity, such as their mothers or teachers. Therefore, their peer-group relationships may be less influential in their later behavior." Boys, meanwhile, are more concerned about status in their peer group, probably because "when they enter first grade, boys are not as used to doing thekinds of tasks that school calls upon," she said. "Successor failure seems to be more important" to boys. Ensminger added that the findings did not apply to harder drugs, such as cocaine and heroin.