So I did mentioned that Namjoon had sufferred MDD in the last chapter. I stumble upon this when Im handling a court trial last two weeks so i think it is fit with this story. And since i did not prefer to make up some weird illness, it is much more better if I input something that we can learn together. So here is what it is meant by MDD.
Major depressive disorder (MDD), also known simply as depression, is a mental disorder characterized by at least two weeks of low mood that is present across most situations. It is often accompanied by low self-esteem, loss of interest in normally enjoyable activities, low energy, and pain without a clear cause.
For further explaination :-
https://en.m.wikipedia.org/wiki/Major_depressive_disorder