You should disclose your illness whenever you feel comfortable. I would say the sooner the better. A few times I have waited a while after I was hired to say something, but I have also mentioned my condition during the interview on several occasions. I would rather know in advance that the organization has a problem with my condition. You will be able to tell by paying attention to non-verbal and verbal cues, even if they do not come out and say so. Even though it is against the law to discriminate, companies can still do it and hide the real reason. So I say if it flows naturally in conversation, and you feel comfortable, TELL them!! If you are lucky you will have a supervisor that is understanding and supportive. I hope that you all will have successful careers, which are fulfilling and make you super duper happy.