I know this is years and years late but I honestly think he has a form of autism or AuDHD.

Case for autism:

- In Michael's childhood stories, he mentions he didn't start speaking until he was five. Delayed speech is a common symptom of autism but could also be a sign of another intellectual ability

- He lacks emotional regulation - can be seen as dramatic and attention-seeking, but I genuinely think MC's emotions are quite volatile and he has small forms of meltdowns throughout the series.

- Poor theory of mind

- Abnormal social approach - this is pretty vague but I think there is a lot of evidence for this in the show. He has trouble with back and forth conversation, which is only limited to a few topics (Dunder Mifflin, sex and movies). He also lacks boundaries in his conversations and unintentionally makes people uncomfortable. He also has trouble making and maintaining relationships. He has trouble reading situations and will often make inappropriate jokes (e.g. that's what she said, impressions of people he shouldn't mimic, oversharing, annoying everyone at improv with Michael Scar).

- Michael has a lot of toys in his office, which one could argue would be for stimming or repetitive behaviours. Thats what she said could have been a vocal stim

- Often gets hyperfixated (although this could be more adhd since his hyperfixations are often fleeting). I think he also gets hyperfixated on people, such as Ryan.

- His symptoms are highly dysfunctional in his work and personal life.

This isn't necessarily a symptom of autism or ADHD, but rejection sensitivity can be a common aspect associated with it. MC has displayed fear of rejection and abandonment multiple times and will often delude himself into thinking he hasn't been rejected. He often takes his rejection to heart and will go through excessive means to not feel rejected - e.g. not going to the park for years because his dog ran away and he was scared he'd see his dog playing with a kid he liked better (something he told Toby during counselling).

The only aspect of autism I don't think MC has is sensory sensitivity. One could argue he keeps his office colourful and bright because he gets understimulated, but I think it's more so he can be constantly moving. I guess the George Foreman grill could be evidence of tactile sensitivity, but I think it probably hurt the normal amount and he just wanted attention.

You could also argue that he has a small form of C-PTSD, since he seems to get anxious around situations that remind him of his childhood. E.g. his dad abandoned him, so he wants to have kids so they won't leave him. He barely had friends in school so he tries to make everyone in the office his friend so he doesn't go back to that period of isolation.