I think the answer to this depends on the school and the specific phrasing of the prompt. Some schools are simply trying to elicit how you respond to challenges (and thus how you might respond to the daily challenges of being a physician), and if you can describe in detail how you overcame this and changed from this experience it may be appropriate. However keep in mind many schools (especially those for which this is an "optional" question) are trying to elicit some aspect of your background that posed unique obstacles to you - while this probably wouldn't hurt you per se, it may not be impactful if read amid other essays talking about, say, the experience of being a refugee or coming out of the closet etc. That said, it's not only for underrepresented students to highlight their struggles. Many very strong applications use this essay to highlight some demographic aspect that made some part of your life difficult, such as being an immigrant or in an immigrant family, being first-generation or low-income, having to learn a new language or adapt to a new country (even if not permanently), etc.