Risk of Attention Deficit/Hyperactivity Disorder (ADHD) and Other Psychiatric Disorders in Siblings of ADHD Probands

Introduction: Attention deficit and hyperactivity disorder (ADHD) occurs more frequently in first-degree relatives. It is believed that this risk is not specific to this disorder but also occurs with other psychopathologies. The study of siblings of ADHD probands is an interesting field since they share common environmental factors.

Methods: This is a narrative literature review. A bibliographic search was performed on PubMed and PsychNet databases and topic-related publications were included without date of publication or study design limits.

Results: Siblings of patients with ADHD have a higher likelihood of having this disorder when compared to controls, with odds ratios (OR) ranging between 11.4 and 13.5. Among these siblings, ADHD prevalence ranges between 26 and 45.2%. Siblings with ADHD and those without ADHD have an increased risk of having other disorders, the most frequent being oppositional defiant disorder (ODD).

Conclusions: Siblings of people with ADHD have an increased risk of having the same disorder. The risk of having another psychiatric disorder markedly increases when the sibling also presents ADHD; this is especially true for ODD, substance use disorder and bipolar disorder.