I believe that the personality is the result of the soul because the soul is the sum total of the personality.. I believe that the soul works through the brain and mind while we are alive in a physical body but after the physical body dies the soul continues to have consciousness and it passes to the spiritual world where the soul takes on another form, a spiritual body.
If a person has brain damage or a disease that affects the brain such as Alzheimer's disease or schizophrenia that can cause a personality change but that is only temporary, while that person is alive in a physical body. After that person dies the soul is no longer affected by the brain so they are restored to their former self and the personality. There is a whole section in the book Gleanings about this that explains it in more detail.
Below is a description of the soul that I wrote up from what I have learned from my religion.
The soul is a sign of God, a heavenly gem whose reality the most learned of men hath failed to grasp, and whose mystery no mind, however acute, can ever hope to unravel.
The soul is not “in” the body but rather it is associated with the body and it directs the body and brain and mind. It is the soul that directs human faculties. As outer circumstances are communicated to the soul by the eyes, ears, and brain, the soul communicates its desires through the brain to the physical body, which thereby expresses itself.
The soul works through the brain and while we are alive on earth in a physical body, but when we die and no longer have a physical body the soul continues to live. It lives forever, and that is why it is called an immortal soul.
The soul is the sum total of the personality so it is the person himself; the physical body is pure matter with no real identity. The person, after he dies and leaves his physical body behind remains the same person, and he goes to the spiritual world where he continues the life he conducted in the physical world. The soul takes on some kind of a spiritual form made up of elements that exist in the spiritual world.
“The human spirit which distinguishes man from the animal is the rational soul, and these two names—the human spirit and the rational soul—designate one thing. This spirit, which in the terminology of the philosophers is the rational soul, embraces all beings, and as far as human ability permits discovers the realities of things and becomes cognizant of their peculiarities and effects, and of the qualities and properties of beings” Some Answered Questions, p. 208