relatives, none of those data were included in the diagnostic process. These investigators reported an age-corrected rate of DSM-III OCD of 2.5% among relatives of probands compared with 2.3% in controls. These data suggest that OCD is not familial. However, when a more broadly defined OCD was used in the analyses the rate among parents of OCD probands was 15.6%. In contrast to the rate among the parents of control individuals was 2.9%. It is noteworthy that these investigators also reported an increased rate of non-OCD anxiety among the relatives. It is possible that, since in this study only direct interview data were used in the diagnostic process, the estimated recurrence risks could have been biased. Lipsitz et al59 examined whether using informant information influenced the recurrence risk estimates. In most family studies of OCD diagnoses are based on all direct interview and family history data collected from informants in the family. When only data from the direct interviews were used to assign diagnoses, there was not a significant increase in the occurrence of OCD among the relatives. The rate of OCD and subclinical OCD for interviewed relatives when no informant information was used in the diagnostic process was 5.4%
