I know nothing about mental illness or addiction except for what I've read in books or seen on TV, so my opinion means nothing. But it always seemed a very odd thing that anyone suffering from an illness of any kind would be expected to just 'get over it'. That's why it's an illness, and in this case a chronic one. If you have a severely broken leg you can't get over that, you can medicate to treat the symptoms and that's it.
As for making jokes... same deal. I guess if I'm close enough to someone that I feel comfortable making fun of any condition they have knowing they won't be upset, I probably would from time to time. But even then it'd need to be very sporadic. It's fine to be at ease around your friends and shoot the shit but there's a very definite line past which you're just being an asshole.