Hello!

In this particular case, since the Scarecrow persona in Batman Begins really is more just a persona he takes on rather than anything actually separate from himself, I would say no. Scarecrow itself would just count as his past memories.

If you want to have him possessed by some malevolent spirit that behaves similar to Scarecrow, I can allow that! But it wouldn't be the same as his alter ego.

I hope that makes sense!