 While  Section 3  focused on what might separate mental from non-mental disorders, and  Section 4  was concerned with how to separate disordered from non-disordered states, Section 6 addresses another aspect of classification: controversies over how different types of putative mental disorders should be distinguished from one another. These controversies, like so many about psychiatry, span the disciplines of medicine, science (including neuroscience and psychology) and philosophy.