[Theory] How valid is this claim about Leafeon?

[BH]

So as you may know, i looooooove the adorable eeveelutions but i went to the polish wiki on the Leafeon species and this was writen:

"After parting with it's trainer, it is unable to learn new attacks due to mental depression."

How valid is this? I know the Leafeons are the most pacifists of the eevee line but i never could suspect my Leafeons would be so downed by me parting with them

None of the pokedex seems to have note on this theory, they only claim that it uses photosynthesis and it's cells are more close to plant than animal

 

[Sheep]

Couldn't find anything about this on the bulbapedia wiki, and a brief google search returned nothing too @_@ seems like it's a made-up fact to me, but if I'm wrong someone please do let me know cause it'd be nice to learn more about lore!