Gin S. Malhi: A critical analysis of concepts in psychiatry.

Gin S.Malhi and Erica Bell: Schizoaffective disorder in not "SAD" just bad

Nassir Ghaemi’s comment

        It is a common mistake to conclude from genetic overlap that there is disease or diagnostic overlap.  The fact that schizophrenia and affective illness overlap in genetic studies may have as much to do with the falsehood of DSM as anything else. Recall that DSM criteria are used in genetic studies and we already know that the huge diagnostic definition of “major depressive disorder” in DSM is scientifically false. If you use a false definition for genetic research, you’ll get false results.

        Separate from the falsity of DSM that invalidates so much genetic and biological research, let’s assume that the diagnostic definitions are valid. Still, overlap between two diagnoses would not mean that they are the same diagnosis, or that they are part of a single spectrum. For instance, the genetics of migraine and “depression” overlap; is migraine the same illness as depression? The genetics of ulcerative colitis and “depression” overlap: same illness? The genetics of asthma and allergies of various kinds overlap: same illness?

        The biology of illness is conservative. The same genes can cause a range of illnesses that are related but are not the same thing.  Some genes are relevant to both schizophrenia and affective illness; so too some genes are relevant to affective illness and migraine, and ulcerative colitis; and some genes are relevant to asthma and shellfish allergy. But it would be false to say that all those diagnoses are just one thing.

October 8, 2020