risk factors and etiology

Write a 2-3 page paper on risk factors and etiology of OCD. Use at least 4 peer reviewed articles. APA style.Explain risks factors and etiology from OCD. Things to include are heritable rates, family structures, theories on the roles of serotonin and the imbic system, especially the basal ganglia, and anything else that you can find. There are other theories and models, none are solidly proven yet, so just say whats out there in the paper.