You may be thinking of (stereotypical) hyperactive ADHD. ADHD inattentive type has little issue sitting still and retreating from reality into the brain (which is why it often goes unnoticed).
The lighter side of ADHD
You may be thinking of (stereotypical) hyperactive ADHD. ADHD inattentive type has little issue sitting still and retreating from reality into the brain (which is why it often goes unnoticed).