is thus uncommon. Individuals with only somewhat different views of school, however, are likely to belong to the same clique, and socialization is likely to decrease their differences over time. For example, girls' decisions about enrollment in advanced math are significantly related to those of their close friends. A study of 78 high schools found that even controlling for past achievement, the GPAs of an individual's close friends reliably help predict grades; in fact "of all the characteristics of friends that influence adolescents' behavior, their friends' school performance has the greatest impact, not only on their own academic achievement, but also on their involvement in problem behavior and drug use." Orientation toward teen culture Similar taste in music and clothing signal others with potentially shared interests and values and often suggest the leisure activities and substance use patterns of which they approve. Thus adolescents emulating similar cultural standards are likely to become friends and these friends are likely to encourage these aspects of their attitudes, behaviors, and dress. Participation in subcultures can also reinforce belonging. In many cases, clique members can be easily identified based on dress alone. Antisocial activity Research does not support the common belief that troubled adolescents have few or no friends. Instead, such individuals gravitate toward one another and form their own cliques, although these friendships do often differ from the friendships of more socially acceptable children. This general self-sorting trend applies in different ways to specific kinds of antisocial behavior. A few of the most studied are substance use, aggression, and depressive symptoms. Substance use Similarity in substance use is one of the most powerful factors in clique development and lasting membership, even serving as the earliest predictor of cross-gender friendships and the most common basis for multi-ethnic cliques. Alcohol and drug use are predicted by the interaction between number of substance using friends, the extent of their substance use, and perceived closeness to those friends; a substance-free adolescent is thus unlikely to seek out or be accepted by a clique characterized by frequent substance use and even more unlikely to remain substance-free long after entering such clique Cliques typically fall into one of four categories and clique membership reliably predicts individual behavior. High Functioning cliques consisted of "a network of high-achieving friends who were involved in school-based extracurricular activities and who reported low use of alcohol and few symptoms of depression." Maladjusted cliques "showed