Okay, first of all I'm no expert in this, but having watched eight episode of Run On already, I've picked up some behaviours that might indicate that Ki Seon Gyeom has Asperger's syndrome, high functioning autism, or ADD (a type of ADHD). Mind you that I don't really remember the particular episodes when these situations occured, so I won't be able to tell you that.

1. He avoids eye contact.
2. He has sudden outbursts of rage and aggression.
3. He doesn't seem to fully understand other people's feelings, emotions, and motives.
4. He  is a picky eater (kind of a trivial thing, but happens in some mental disorders).
5. He doesn't know how to read the room.
6. He has problems with expressing his emotions.
7. While having a serious conversation with his mother, he suddenly becomes distracted for a split second by a small thing that happens in the background that isn't even in the focus in the particular scene.
8. People around him say that he's living in his own world and doesn't pay attention to this surroundings.

What are your thoughts? Do you think I'm reading too much into things? Or has anyone else—who knows more about Asperger's syndrome, autism, and ADHD—noticed the things I have? Honestly, I'd love to see more awareness in dramas about various types of mental disorders. For example, I believe that It's Okay to Not Be Okay depicted autism pretty well.

What are your thoughts?

He might be on the spectrum, good notes!

I don't  think so. He is the way he is because he grew up sheltered with no friends or family to take care of. He didn't have enough human interaction and so he grew up to living in his own world all alone. So he might come off different to other people. But I think he is pretty normal considering the way he grew up and the way he saw the world and the people in it. He is someone who is definitely observant, smart, considerate, calm and composed, knows his limits, strong minded, strong morals and he knows how to take care of people he cares. He is a very strong individual both physically and mentally. His personality and mental state are all fine. He only need to learn more about interacting with people, to have someone he can lean on and trust and to not be alone or lonely. He have to learn to love himself, to feel the warmth of love and feelings like home and family. Mijoo herself said he is a mentally strong person. 

I'm on the first episode and I realized these things as well, had to see if others noticed, through his expressions and social interactions along with never understanding those around him it was evident he has to be on the spectrum. I love that it wasn't advertised in preview and trailers. 

you are so right. i noticed that to, and because of that i think this whole serie was boring !!!

As someone on the spectrum, it is quite easy to spot them in anyone- even those who aren't. His eyes have given me the effect since the beginning that he is aloof. His character doesn't seem to know what certain things mean due to being neglected by his mother growing up and given a hard time by his father. Thus, he is learning how to share, how to cope (journaling), and how to love. 

I am thinking that rather than being on the spectrum, his lack of affection growing up (+his mom always leaving to shoot movies) and loneliness (him mentioning that he likes hearing others in a house) is giving off that impression. We as the audience now see that he is learning everything as he is finding himself in a normal, mundane life rather that of a famous athlete.

He is one of of the few characters from dramas that is actually similar to me . :°°° D I think it's just our personality... tho I had some people who thought I had Asperger's or something LOL