a result of individuals seeking care at mental health hospitals/clinics can inadvertently exclude those with milder forms of the disorder who may seek treatment from primary care providers and/or those who do not present to clinical services at all. If such individuals were included and if their genetic architecture were different from our current OCD case sample, it would impact the estimated heritability. By restricting cases to individuals in Sweden, we had a genetically homogeneous sample, which minimized the risk of confounding due to population stratification and facilitated the combining of the cohorts. Nonetheless, it does limit the generalizability of our results. However, after combining our results with those of Davis et al., we observe results that fit expectation, thus suggesting that the results are likely to relevant for most populations.
