Unlike many theoretical approaches to psychotherapy, existential therapy is based primarily on a guiding philosophy of exploring the subjective client experience rather than specific types of therapeutic techniques. It is an approach that is said to be appropriate for use with a variety of client types and within different therapeutic settings. Initially based on the ideas proposed by Soren Kierkegaard, Jean-Paul Sartre, and other existential philosophers, the foundations of existential therapy have developed over time through the influence of several psychological theorists such as Otto Rank, Victor Frankl, Irvin Yalom, and Rollo May. The key philosophical points of this therapeutic orientation focus on personal responsibility, self-awareness, and creating meaning in the face of a chaotic and absurd existence.
As a theoretical model of psychotherapy, existential therapy places primary importance on understanding the client's internal experience of the world. While this approach tends to support an eclectic use of psychotherapeutic techniques garnered from other orientations, existential therapy is not formulated on the use of any specific set of techniques. Existential therapy is viewed as particularly appropriate for clients in developmental crisis, such as grief, career transitions, or adolescent identity exploration.
One facet of existential therapy, borrowed from its initial philosophical influences, is the cognitive framework describing the individual's three ways of existence within the larger world. The immediate biological environment outside of the individual's self is called Unwelt. Mitwelt is the term for a sense of unity and belonging within the external world, the self within a community of other people. The inner world or self-relationship is known as Eignewelt.
In its theoretical worldview, existential therapy overlaps in several ways with the humanistic and transpersonal approaches to psychotherapy, which emphasize the human tendency toward self-growth whenever supportive conditions exist. Within all three theoretical models, the therapeutic relationship between client and therapist is seen as the central active component of therapy. Rather than the therapist acting as a blank screen, as in some psychoanalytic models of therapy, the human self of the therapist interacts authentically with the self of the client to create a collaborative therapeutic path. As with many humanistic and transpersonal therapists, a clinician who practices existential therapy might proceed cautiously in the use of a clinical mental health diagnosis. Some existential practitioners might choose to avoid clinical diagnosis entirely.
Victor Frankl developed an existential approach to psychotherapy, called logotherapy, based on his personal experience in a concentration camp. His experience is described in the book Man's Search for Meaning. Another existential therapist, Irvin Yalom, is best known for his theoretical approach to group therapy.