Probably…maybe. As an adult with ADHD, I usually found the challenge and amount of information very engaging in higher level and graduate courses. Doing well was easier but I didn’t always do better.
Higher Level Courses
In general, regardless of level, I would say people with ADD/ADHD do better in courses in which they have interest in and are engaged. The higher-level ones may provide more challenge to engage the ADHDer but could also frustrate and confuse. The research-based aspect would allow more in-depth study of outside reasearch providing novelty which could prevent boredom or distract the ADHDer from getting any work completed.
I feel ADHD should not be the deciding factor in whether a person should pursue their academic goals.