A recent study in the Journal of Sleep Research found that undergraduate students with ADHD are more inclined to be evening types and exhibit depressive symptoms. The research, encompassing 4,751 students, also highlighted a strong association between inattentive ADHD symptoms and depressive tendencies among evening-type individuals. ...
Well now I’m curious, what’d you learn?
“To a tittle” came first and likely “to a T” is an abbreviation. But sounds like no one’s completely certain. Both occurred in 1600s.
tittle /tĭt′l/
Longer explanation here: https://www.phrases.org.uk/meanings/to-a-t.html