@
Silentshade
@
Royal
Hate to contradict people but...
Goosefeather was insane because of his curse. He was haunted with the visions of the future and the inability to stop the tragedies coming. He could never tell anyone because he was taught not to, as they would see he was insane. Thus, he acted out instead of flat out saying he's seen the future. He says he has 'visions' (which he has but normal Medicine Cat visions don't stretch too far into the future) and those take him for insane because of his impulsive worrying. He was most likely traumatized by the Leaf-bare without prey in Goosefeather's Curse, and began to have anxiety from then on out.
And @
Lawlipop I agree! You make a very good point.