Mikan is an extremely meek, paranoid and fragile individual who suffers from hazardously low self-esteem as a result of severe abuse and bullying. This has resulted in many behavioral symptoms such as being easily intimidated, breaking down and crying with little provocation, profusely apologizing and nervously stuttering while speaking. She constantly worries about annoying, boring or offending others, going so far as asking Hajime Hinata if it would be alright for her to remember his name when introducing herself. This delicate persona makes her a natural target for Hiyoko Saionji's instinctively predatory and cruel personality. However, as the Ultimate Nurse, Mikan tends to act much more confident while doing her job, and she is decently knowledgeable and intelligent. Her medical knowledge proves to be useful in murders, as she provides autopsy reports, including information on the corpse's state, details on injuries, cause of death, and time of death. Furthermore, she sometimes gives (often unwanted) health advice to others concerning things like eating and sleeping, and may occasionally start to describe things like bodily functions in way too much detail in her wish to give the other students' information on the subject at hand. Unlike most students, Mikan has even mentioned that she likes being on Jabberwock Island, because her classmates acknowledge her and her talent makes her useful.

https://www.youtube.com/watch?v=5zOsurPMglA&t=4s