Older sibling correlates of younger sibling drug use in the context of parent-child relations.

The purpose of this study was to examine older brother correlates of younger brother drug use in the context of parental influences and younger brother personality. The sample consisted of 278 White male college students and their oldest brothers, who volunteered to answer self-administered questionnaires. Results indicated that 3 domains of influence each had an independent impact on younger brother drug use: (a) parent-younger brother relationships and parent drug use, (b) older brother-younger brother relationships and older brother drug use, and (c) younger brother personality. Modeling of nondrug use and a strong attachment relationship in the parent-younger brother and sibling dyads, as well as younger sibling traits of conventionality, had strong links to low younger brother drug use. Our findings highlight the importance of modeling and mutual parent-child attachment relationships as well as sibling relationships as they relate to the possible etiology of drug use.