The familiality of specific symptoms of obsessive-compulsive disorder

This study aimed to assess whether a family history of specific OCD symptoms was associated with the same OCD symptoms in study participants. Participants were sampled from the Nepean OCD study (N=206) and were assessed with the Yale-Brown Obsessive-Compulsive Scale Symptom Checklist (YBOCS-SC) and the Vancouver Obsessional Compulsive Inventory (VOCI) in order to determine their OCD symptoms. A family history screen was used to determine whether participants had a first-degree relative with a history of any of the following specific symptoms: hoarding, contamination/cleaning, symmetry/ordering, doubt/checking and/or other OCD symptoms. The characteristics of participants with a family history of a specific OCD symptom were compared to those of participants with a family history of any other OCD symptom. This was repeated for each specific OCD symptom. The roles of co-occurring tics and age of onset of OCD were also assessed. Distinct familial associations were detected for the symptoms of hoarding and contamination/cleaning. Age of onset of OCD was significantly younger in participants who reported a family history of "other" symptoms. These findings suggest that certain OCD symptom dimensions are more familial than others, which has significant implications for aetiology of OCD. Crown Copyright (C) 2016 Published by Elsevier Ireland Ltd. All rights reserved.