Maybe. Charles Whitman had a brain tumor, but they don’t know if that caused him to climb the UT Austin clock tower an start shooting people.
https://en.wikipedia.org/wiki/Charles_Whitman
“There was a rumor about a tumor
Nestled at the base of his brain.
He was sitting up there with his .36 magnum
Laughing wildly as he bagged ‘em.
Who are we to say the boy’s insane?”
from The Ballad of Charles Whitman, by Kinky Friedman