I’ve identified some people in Daria with PTSD:

(possibly most obvious) Mr. Morgendorrfer. He dad was emotionally abuse and neglectful I’ve when he was a child. During family conversations, Daria’s dad is always going off on uncontrollable tangents about the abuse he suffered as a child.

Ms. Barch, the teacher: her husband took her for granted and abandoned after 22 years. She hates all men, goes off on uncontrollable tangents about her husband. She is even rude and abusive to her male students.

How about Mr. DeMartino? He’s always yelling at the students, has the bulging eye. Was he in a war? There’s that one episode where he and Mr. O’Neill share a hotel room during a teacher’s convention and Mr. DeMartino seems to yell in his sleep…?

Please feel free to add or go into more detail! I’m really finding it interesting that there are characters with such clear psychological damage on Daria.