There is an important distinction between the "groups" that navigate from the bottom of your hubs and the "categories" that are used on your profile page.
Groups do not appear on your profile page; categories do--five of them at a time. They won't appear on the profile page at all until you write your 15th hub. No hub will appear there unless you have at least two hubs in a category. The subcategories can differ, but it--the HP computer--will look for a lowest common denominator among your hubs so that it can list at least two of a (sub)category.
These categories on the profile page can be manipulated by the category you assign to each hub. Most hubs can be categorized in more than one way, e.g. your hub on Mental Health and Employment. If you re-categorize that under "Business and Employment," it will no longer list with your hub on Bi-polar. In fact, neither will list on the bottom of your profile page unless there you have published at least one more in some subcategory of "Business and Employment" or "Health."