Ego identity: developmental differences and experimental substance use among adolescents.

A total of 12,988 adolescents completed a questionnaire which assessed experience with cigarettes, inhalants, alcohol, marijuana, cocaine, and level of ego identity (EOM-EIS). Discriminant analyses of substance use, across the achievement, moratorium, foreclosure, and diffusion identity statuses, yielded significant functions for each grade comparison (7th to 12th). Frequencies of experience for diffused respondents were consistently higher than estimates for the achieved and moratorium respondents; and, foreclosed adolescents reported the lowest frequency of experience. Diffused adolescents were about twice as likely to have tried cigarettes and alcohol, three times as likely to have tried marijuana, four times as likely to have tried inhalants, and five times as likely to have used cocaine than their foreclosed peers. The achieved, moratorium, and unclassified respondents reported frequencies of experience that fell between the two extreme groups. Implications for identifying adolescents "at risk", and tailoring prevention/intervention efforts to address developmental differences are addressed.