Aims: To evaluate the effectiveness of a brief intervention enhanced by a consistent support person in facilitating attendance for substance use treatment following a hospital alcohol or other drug (AOD) presentation. Participants: We recruited 127 adolescents (aged 12-19 years) from hospital emergency departments, 57 were female. Sixty were randomly assigned to receive the intervention and 67 to receive standard hospital care. For the purpose of comparison, normative data were also collected (at baseline) from 122 non-AOD presenting adolescents. Intervention: The brief intervention involved identifying impediments to treatment service attendance and facilitating attendance via a consistent support person. Results: At 4 months, a significantly greater proportion of the intervention group, both daily and "occasional" drug users, had attended treatment than the usual care group. Regardless of attendance at the treatment service the intervention group showed a greater improvement in GHQ-12 scores than the usual care group. Across groups, a greater proportion of those who attended treatment moved to "safer" drug use behaviour (non-hazardous alcohol consumption and/or non-injecting drug use (IDU)), and showed a greater decline on a composite total drug use score. Conclusions: Adolescent attendance for treatment can be improved by brief intervention with harmful substance use behaviours reduced for both "occasional" and daily users. Improvements in psychosocial well-being is observed regardless of attendance at a treatment service. (C) 2004 Elsevier Ireland Ltd. All rights reserved.