i think true, but that is just based on fictional characters i have read about-
Peeta Mellark is one of them- in the books, he isn't too rebellious, but he is definitely described as being isolated, passionate, and melancholic.
Gale Hawthorne is another- He is rebellious, passionate for what he believes in and towards Katniss. a lot of the time in the books he seems melancholic, not very isolated, but i think you get the point.