I would also like to add that I have Chronic Fatigue Syndrome, and when I have told people about it, to let them know the reason why I sometimes can't make plans or show up for meetings, some of them scoffed and were angry with me, whereas when they just thought I was lazy and unreliable they were fine with it.
Disclosing an illness is a thorny issue. I don't tell anyone I have AS except the people I'm close to, and not even my family.