Among the psychologial sciences that have studied transpersonal phenomena we find the schools of Transpersonal psychology, Humanistic psychology and Near-Death Studies. Among the forerunners to the development of transpersonal theory we find, the school of Psychosynthesis (founded by Roberto Assagioli), and the Analytical school of C.G Jung.
In integral theory, transpersonal refers to stages of human development through which a person's self-awareness extends beyond the personal. Integral theorists include Ken Wilber, Michael Murphy, Michael Washburn, Allan Combs, Jean Gebser, Don Beck, and Clare Graves. The work of all of these theorists is inspired, in varying degrees, by the writings of the Hindu philosopher Sri Aurobindo.
As is embedded in the concept of personal growth by the transpersonal movement, personal goal achievement will necessarily involve the possibility of an arational mutation of the relationship between the subject and his/her goal. That this may occur in the process of realisation. It may also be embedded in the transpersonal movement that such a mutation will cause a cultural change that may be termed as an panepidemic memetic flu or a cultural and rhizomatic virus project.
Transpersonal psychology considers the concept of transpersonal states of awareness. Stanislav Grof defines these: "The common denominator of this otherwise rich and ramified group of phenomena is the feeling of the individual that his consciousness expanded beyond the usual ego boundaries and the limitations of time and space."  These include mystical states and near-death experiences also subject to the psychology of religion. The idea of altered 'states' of awareness is pivotal to this research. The conceptualisation, and other signifying processes of altered forms of awareness are studied in transpersonal psychology. Transpersonal psychotherapy consists of moving between these states,and learning techniques for disassembling and reassembling on different states/situations of altered realitymontage for the purpose of healing, which can be brought about by transpersonal psychotechnologies. This clarifies one of transpersonal psychology's roots in early psychedelic work, some of these psychotechnologies include research with psychedelic plants and chemicals such as LSD, ibogaine, ketamine, peyote, ayahuasca and the vast variety of substances available to all human cultures throughout history. See: "Part III. Transpersonal Dimensions of Healing with Psychedelic States" Vol. 2. It can also be said that the attempts by transpersonal psychology is an intercultural approach to medicine and etnobiology understood as a discourse raised from the academic community of the globalised university sector of knowledge production encountering the so called herbalist shaman or alchemist.
2. Winkelman, Michael J, and Thomas B. Roberts (editors) (2007). Psychedelic Medicine: New Evidence for Hallucinogens as Treatments Westport, CT: Praeger/Greenwood.