Crohn's disease used to be rated at 10, 20, and 30% but has since been reevaluated as of 2011. It is now rated at 10, 30, 60, and 100%. I rate 30% provisionally, as my flare hasn't really stopped since 2007 so it can be officially stated that I only had 1 flare... but due to chronic treatment with corticosteroids or other drugs for management... they rated me 30.
Here is 60%: 60-percent evaluation
for any of the following: multiple
attacks or flareups of Crohn’s disease
per year with abdominal pain or
tenderness, diarrhea, fever, anorexia
(lack or loss of appetite), and fatigue
plus substantial weight loss and anemia;
hospitalization two times per year for
recurrent complications such as abscess,
stricture, obstruction, or fistula; or
constant or near-constant treatment with
high dose systemic (oral or parenteral
[intravenous or intramuscular])
corticosteroids.
This is just for Crohns. Since you likely have other issues (mental) that may be associated with it, you can get more. Ever break a bone? That can give you 10% even if it healed right. Knees hurt? 10% Depressed or anxious all the time? Talk to someone and get a diagnosis and that is 10-60% dependent on your GAF. My GAF is 58... my cognitive functioning is higher than most which is why my GAF is higher than most with chronic depression, fatigue, general irritability, and anxiety disorder NOS (though I think it is social anxiety... with just dummies). I only filed for my knee and crohn's currently to get my foot in so I have a provisional of 40%. I have one year for my crohns to be reassessed. If I don't go into remission or get surgery for my fistula... and the VA confirms my fistula (my GI doc is a MORON) I will be at 60%.
As for military separation... that is pending. Because I am NG, my state wants to try and boot me out without the MEB, but because NGB has approved my LODs... they have to grant me an informal MEB with referral to a PEB. I will probably be at 10-20% for depression, anxiety, patella femoral pain syndrome, and crohns... the military likes saving money. If I hit 30%... retirement.