Is the familial/sporadic subdivision a method of genetics?

Subdividing a sample of patients on the basis of family history into familial and sporadic cases is a simple research method whose purpose is often misunderstood. What it can do is to reveal etiological heterogeneity by refuting a hypothesis of homogeneity. If familial cases prove to be different from sporadic cases in some respect, the question of a refutation arises. Homogeneity is usually assumed in genetic work on schizophrenia. This assumption is also widespread outside genetic circles, but it is not necessarily true. If it is false, research into the causes of schizophrenia must be redirected. The author claims that the use of familial/sporadic subdivisions is a clinical research method that does not require genetic expertise. Geneticists may frown upon it for its lack of sophistication, but the important thing is whether it works in actual attempts to refute the homogeneity view.