I am a huge fan of Invader Zim and I think Zim has some form of autism/general spectrum disorders. It could be a complete coincidence, but there is a butt load of evidence to stake my claim.
Not only was he born with a defective PAK (basically his brain), he shows little to no volume control (compared to other Irken we see in the show, he is quite the boisterous one), rarely picks up on social cues (when Tak pranked him, he thought her love was for real, and again, compared to other Irken like Tak, he is much less skilled at, considering she in particular blended in perfectly), and experiences extreme sensory overload in Walk of Doom, bolting out of the city as soon as possible. He obviously shows little to no empathy for, well, anyone, but a " cold unfeeling robot arm ", which could also be an object Zim clings to.
What do you guys think? Is it pure coincidence or is it more just general anxiety and unfamiliar-ness with his environment?
_________________
" If I'm really as evil as you say I am, then let God strike me down where I stand.....
HA! Nice try, jackass! Next time, give it your a-game! "