Board Thread:Versus Debates/@comment-31377172-20200228010635/@comment-26636534-20200302221244

The term "mental damage" was used very loosely in the instance with Tsunade yeah. Tsunade didn't seem to be using a particularly taxing or risky healing jutsu either, it actually looked like a conventional mystical palm technique. So you are probably correct in saying it's due to complexity. Although, 'Samehade regeneration' seems quite complex to me.