This is why an empath can feel emotions from other individuals so acutely, the waves that are being emitted by other animals around them causes their own HEF to react during absorption and creates a tangible response that they can categorize into a human feeling.
So one kind of wave would be associated with anger and another with depression, the empath isnt taking the emotion from another being but they are, being highly sensitive to energy vibrations, interpreting the energy that other organisms are emitting.
Around 5,000 years ago in India people began to refer to an energy that was thought to be the universal source of all life, they believe that this energy permeates all aspects of our environment and flows through every living being and is even created by our environment.
They called this energy prana, in China it is called Qi, in the Kabbalah it was referred to as Astral Light, by scientists and philosophers it has been called Orgone, Somatid, Bioplasma, Biofield, the Odic Field, Aura, and much more.
As the energy is absorbed, it affects the person receiving it and therefore gives the empath a physical response by causing altered vibrations of their own HEF.Unfortunately while there is a hypothetical cure for Psi Vamps out there, the logical implications of cutting yourself off from everything that could provide the individual energy waves to feed on is not feasible.Many Psi Vamps would or already could, feed on the waves that a plant emits, or a small form of life.Many times in life we end up doing something without being fully aware of the fact that we are indeed performing an act, at times Psi Vamps are not aware that they are draining others but are still doing so.Their conscious mind is not focused on the act of energy harvesting but their body is actually going through the process of garnering energy from their environment, be that human, plant, or other animal.