The level of an adolescent's externalizing behaviors, which are often the manifestation of poor regulatory abilities, is highly influenced by peer relationships (C. A. King & Young, 1981; Lahey, Green, & Forehand, 1980). Data from a national longitudinal sample of youth (n=1,725) revealed that peers exert a stronger influence than family on adolescent drug use (J. P. Hoffman, 1993). Similar findings were produced in a longitudinal study of African-American youth, designed to identify the risk factors for drug use in the sample (n=380). Researchers found that, even after controlling for family relationship variables, the adolescent's relationship with delinquent peers strongly predicted the use of marijuana, alcohol, and other illicit drugs (Friedman & Glassman, 2000). Finally, adolescents' peer relationships may also be associated with delinquent behavior. Longitudinal research of 763 predominantly white adolescent girls found an association between antisocial peer relationships and the initiation and continuation of delinquent behaviors (Talbott & Thiede, 1999).