I had to dis-enroll from high school at one point. I know that you are talking about college classes, but I was taking online classes through BYU. I would say that it really depends on your style of learning. I am a kinesthetic learner who really does better in an interactive setting (where I can listen to the professor, ask questions, etc.) I was getting Bs and As in regular school with my symptoms (until they got so bad that I was hospitalized- hence my dis-enrollment). And I was failing online classes with little-no symptoms. I just couldn't deal with everything being read the material, take an online test format.