The hypnotic state is generally considered to have many similarities to those found in deep states of meditation or even sleep (especially during the dreaming phase). The use of trance states is found in most cultures and is often associated with healing or even in religious rituals. Evolutionarily speaking, scientists have speculated that our ability to access trance states may perform a healing function for the body and mind. Modern hypnotherapy is generally very goal directed and has been used extremely effectively for a large number of personal and health issues. Many psychologists believe it to be the most powerful medium of therapy we know of.