IMO Buffy and Peyton have suffered a lot more than anyone else on the list. Every one has had their tough times, but it seems like with these two the tough times wouldn't ever stop.

& Veronica.

Also Peyton & Veronica

I'm pretty sure none of the others has went through what she went through. not even close.

I don't know Buffy, so I gotta pick Peyton

She was chosen to be a warrior and the only person in the world capable of fighting evil. Her life was dictated for her since she was fifteen and forced to risk her life daily in order to save the world. She was extremely lonely and had to live a secretive life in order to protect the people she cared about. She was never given the privilege of making decisions based on what was best for her... she always had to focus on the well-being of the world before she could care for herself. It was her job to remain selfless and sacrifice any sort of normalcy in order to protect the world. She died twice. She went to heaven one of those times and was finally at peace and then ripped out of heaven by her friends and brought back to this violent world. Her parents got divorced and she blamed herself. Her father eventually cut her out of his life. Her mother died. Many close friends of hers died. A psychotic murderer stole her identity. She was forced to kill her first love in order to save the world. She had to stand there and watch another man she loved die in order to save the world.

Plus the ordinary problems of being teased at school, having a guy use her for sex...etc.

I love Buffy and don't really like Payton but objectively Peyton means black 0_0

Her boyfriend broke up with her without a word of explanation. Her best friend was murdered. She saw her best friends dead body when her dad was called to the crime scene. Her dad was forced to leave his job as sheriff in disgrace because he was trying to find justice for her best friend. She had to move because they couldn't afford their lifestyle any more. Her mother skipped town, left her and her father alone. She was forced to choose between her friends and her father, and became social pariah, shunned by all her former friends when she stuck by her dad. She was drugged and raped at a party, then mocked and laughed at when she tried to report it (also she gets an STD from the rape). She dedicates her life into finding the killer of her bff. Her mother cheated on her father, she founds out that her bff and her ex boyfriends father might be her father (thankfully he was not) not to mention she's almost always in danger solving crimes and helping people. When she found out who killed her best friend (her at the time boy friends father) the killer locked her up in a freezer and set it on fire. Thankfully her father rescued her.
She found out that one of her peers raped her, gave her an STD, killed everyone in a bus crash (which she was supposed to be on) triggered a bomb on a plane which she thought her father was on (he was not)made her believe he killed his girlfriend whom is a friend of hers and he wanted to kill her by wanting to jump of the roof of a hotel.
And that's just a glimpse of how her life was, this all happened while she was just a teenager.
plus all her problems with her friends, boyfriends, peers, money, etc.
It doesn't get much better when she gets to college... She doesn't get into her dream college (Stanford) because she doesn't have enough money and didn't get the scholarship because she had to attend the trial of her bffs killer, who was found not guilty (he was killed though)
There is so much more things that happen in her life

Veronica Mars didn't even get an happy/ good ending...
And she didn't end up with her love of her life (who to me is Logan Echolls)

She has been hurt, emotionally, sexually and physically... way to much for any person... words can't describe the amount of pain and heartbreak that she has had... but she pulled through everything.

They all suffered a lot !

^Agreed

But I think Elena and Katherine suffered the most, I didn't watch Buffy the Vampire Slayer so it's not fair if I judge.

Izzie, Meredith, Katherine Jenny & Peyton<3