The “Younger-Sibling-at-Risk Design”: a Pilot Study of Adolescents with ADHD and an Older Sibling with Substance Use Disorder

Abstract

Introduction: This article introduces a “younger at-risk sibling” design to study progression from other psychopathologies to their substance use disorder (SUD) complications. The design selects not-yet-SUD adolescents with high-risk-for-SUD psychopathology only if an older sibling has SUD. This “proof of concept” pilot study examines the design’s feasibility if the younger sibling has attention deficit hyperactivity disorder (ADHD). Method: Subjects were recruited from families at substance abuse treatment centers that had a non-SUD younger child with ADHD, from families at behavior disorder clinics that had a younger child with ADHD and SUD older child, and through general advertisements. Subjects were seen weekly for at least 3 months and monthly thereafter for 3 months. All were treated with open-label lisdexamfetamine dimesylate 30–70 mg per day. Outcomes explored were recruitment, compliance, diversion, ADHD improvement, and substance use interest. Results: 25 families were screened, 13 evaluated, and 8 began medication. ADHD Rating Scale-IV scores obtained by parent–adolescent consensus improved as expected with a stimulant. Rating forms could quantify substance use interest in subjects with some drug culture exposure but encountered a floor effect in those without. The design’s complexity and implicit commentary on family dynamics complicated recruitment but may have facilitated retention. Conclusion: Sibling pairs in which the older sibling has substance use and the younger sibling has ADHD exist. Such younger siblings can be recruited into a treatment study. The design may shed light on the pathogenesis and prevention of SUD complications from ADHD and theoretically other SUD comorbidities.

• comorbidity
• pathogenesis
• family
• siblings

ACKNOWLEDGEMENTS

The authors acknowledge career development support by the National Institute on Drug Abuse, K02 DA 00451, Stephen Donovan, Principal Investigator and K24 DA 029647 Frances Levin, Principal Investigator.

This study was sponsored by Shire Pharmaceuticals.

Declaration of Interest

The authors report no conflicts of interest. The authors alone are responsible for the content and writing of this paper.