It is true that one who is steeped in the world of Torah generally does not suffer corruption of character, but that is not the primary purpose of the mitzvot.
On the other hand, the Torah would never command us to do something that clearly damages or destroys the body.
The Midrash states, “Nothing that is evil descends from above” (Genesis Rabba).
In other words, no mitzva would be given that causes damage, whether physically or spiritually.
That said, it is still quite a stretch to then pin everything on this point and search for each mitzva’s physical and personal benefit.
God did not descend on Mount Sinai to provide information that can be found in a cheap psychology textbook – to explain how to improve one’s life and how to behave better.
The psychological explanations for mitzvot are even worse than the medical explanations, which the Maharal criticized sharply, asking if it is conceivable that the Torah amounts to an article in a medical journal (Tiferet Yisrael 8).
In his time, at least, medical and psychological texts were expensive and difficult to access.
Nowadays, most of this information can be found easily, for free, on the Internet.
If this is the case, could it be that for that purpose alone God Himself descended from the heavens?
Rabbi Adin Steinsaltz