The role of older brothers in younger brothers' drug use viewed in the context of parent and peer influences.

The purpose of this study was to examine the impact of an older brother's drug use on his younger brother's drug use viewed in the context of parent and peer influences. The sample consisted of 278 White, middle-class male college students and their oldest brothers, who were given questionnaires assessing drug behavior. Results indicated that older brother, parental, and peer drug use each had an independent impact on younger brother's use. The degree of influence varied, with drug modeling by peers and older brothers having a stronger association with younger brother drug use than did parental drug modeling. Further, the older brother's advocacy of drugs was associated with his younger brother's use even if the older brother did not serve as a drug model. Similarly, older brother drug modeling was of importance even if he did not advocate use. Finally, interactive results suggested that older brothers who did not use drugs could offset the negative effects of parental drug risks on younger brother use. Also, younger brothers were least likely to use drugs if both older brothers and peers served as models for nonuse.