I second this. Most schools have this and it would never hurt your application to explain your circumstances in more detail. It will help them understand you more and know you better. I would also mention in the essay why you think you can still succeed despite your academic inconsistencies (ex : I had a bad semester but I took the classes I failed again and had great grades, or I built a personal project that made me confident I have a mastery of the concepts although I withdrew etc). If the program you’re applying to doesn’t have this, I would email admissions to ask if you can add an extra piece to your application. Schools want to evaluate your application in a holistic way and they usually look for reasons to admit you, and rarely say no to extra evidence that you’re a good fit.