also possible that an affected relative who has sought treatment or proband may “over-report” symptoms in their relatives. In the Lipsitz et al59 study, family history information was only collected from the affected probands, all of whom had sought treatment, so it is possible that there was “projection” of their own behaviors onto their relatives, resulting in over-reporting of affected status. However, in other studies where family history data were collected from all interviewed relatives,3,8,56 information was collected from both affected and unaffected relatives, and therefore it is less likely that there would be overreporting of OC symptomatology, since unaffected relatives would not be “projecting” their own behavior onto their relatives. Of note is that in the study of Lipsitz et al,59 an increased rate of other non-OCD anxiety disorders was observed. Finally, Black and colleagues did report that a number of family members were reported to have OC symptomatology by their relatives. Thus, it is possible that, if all available information had been used to assign diagnoses, the recurrence risk for OCD among first-degree relatives could have been higher than reported.
