Given that the majority of studies demonstrated that OCD is familial, and twin studies suggest that this familiality is in part due to genetic factors, the next step has been to examine whether the mode of transmission in these families can be explained by specific genetic models. Complex segregation analyses allow an examination of specific genetic models by estimating the “goodnessof-fit” of the pattern of transmission specified by an hypothesized genetic model to that of the observed patterns of transmission within families. While complex segregation analyses do not prove the existence of genes that are associated with OCD, results of these analyses can reveal patterns of transmission within families that may be helpful in future molecular genetic studies.
