“Rituals or rivalry?” The phenomenology and treatment of sibling specific obsessions in paediatric obsessive-compulsive disorder

• Young people with OCD can present with specific fears relating to a sibling.
• Sibling obsessions can lead to high levels of family conflict and dysfunction.
• Sibling obsessions to not reflect an underlying rivalry or resentment.
• Careful assessment is critical in identifying sibling obsessions.
• Sibling specific obsessions can respond to standard treatment for OCD.

Obsessive-compulsive disorder (OCD) is highly heterogeneous, and can be difficult to assess and diagnose particularly when unusual symptoms are present. This case study (n=9) describes an under-reported presentation of OCD in youth, whereby the patient experiences an obsessional fear of a sibling. Clinical characteristics of this presentation are discussed and comparisons with sibling rivalry disorder are examined. Seven of the participants engaged in a standard treatment protocol for OCD (comprising cognitive-behaviour therapy with or without an SSRI medication); five achieved remission. This presentation of sibling obsessions should be recognised as OCD, and be treated with evidence-based interventions for OCD.