Jungian psychology is a theory developed by Carl Jung, and is central to Analytical psychology (the "Neopsychoanalytic school"). Jungian psychology is geared largely toward the nature of symbolism and the effects of attachment upon the ability of people to live their lives in ignorance of their deeper "symbolic" natures. His ideas center on the understanding that a symbol loses its symbolic power when it is "attached" to a static meaning. The attached and therefore static meaning renders an amorphous symbol (like the sphere or the ourobouros) to a mere definition; no longer does it have the ability to be active in the mind as a "transformer of consciousness," free to associate with new experiences and thinking. "Symbolic power" transcends and permeates through all conscious thinking.
Jung is best known for his term "archetype" which connotes a structural view of psychological life. The term archetype can be understood as quite similar to - and was probably directly influenced by - Kant's term "a priori." Jung often seemed to view the archetypes as sorts of psychological organs, directly analogous to our physical, bodily organs: both being morphological givens for the species; both arising at least partially through evolutionary processes. Current Jungian-influenced thinking has explored nearly diametrically opposing paths from Jung's structural thinking. Some have pursued deeply structural views, along the lines of complexity theory in mathematics, and some have tried to work with Jung's ideas in a seeming post-structuralist way (most obviously, James Hillman). Jung's work with mythology and archetypes was one of the most significant influences on mythologist Joseph Campbell.
Perhaps the most important archetype to Jung would be what he termed the "Self." It could be described as the ultimate pattern of psychological life; he characterized it as both the totality of the personality, conscious and unconscious, and the process of becoming of the whole personality. It could be described as both the goal of one's psychological life and that which pulls one toward it teleologically. One important point to note here about Jung's thinking is that he did not hold to be absolute the four-dimensional space-time continuum that we conventionally conceptualize (see synchronicity).
We can better understand Jung's views of the Self by looking at two other archetypal or structural views that were highly important to him: the idea of "the opposites" and his work describing many old, largely despised and forgotten alchemical texts. Jung saw these texts as valuable psychological treatises rather than dry descriptions of arcane magical practices.
Early in Jung's career he coined the term and described the concept of the "complex". Jung claims to have discovered the concept during his free association and galvanic skin response experiments. Freud obviously took up this concept in his Oedipus complex amongst others. Jung seemed to see complexes as quite autonomous parts of psychological life. It is almost as if Jung were describing separate personalities within what is considered a single individual. But to equate Jung's use of complexes with something along the lines of multiple personality disorder would be to stretch the point beyond breaking.
Jung saw an archetype as always being the central organizing structure of a complex. For instance, in a "negative mother complex," the archetype of the "negative mother" would be seen to be central to the identity of that complex. This is to say, our psychological lives are patterned on common human experiences. Interestingly, Jung saw the Ego (which Freud wrote about in German literally as "the I", one's conscious experience of oneself) as a complex. If the "I" is a complex, what might be the archetype that structures it? Jung, and many Jungians, might say "the hero," one who separates from the community to ultimately carry the community further.
Jung's writings have been of much interest to people of many backgrounds and interests, including theologians, people from the humanities, and mythologists. Jung often seemed to seek to make contributions to various fields, but he was mostly a practicing psychiatrist, involved during his whole career in treating patients. A description of Jung's clinical relevance is to address the core of his work.
Jung started his career working with hospitalized patients with major mental illnesses, most notably schizophrenia. He was interested in the possibilities of an unknown "brain toxin" that could be the cause of schizophrenia. But the majority and the heart of Jung's clinical career was taken up with what we might call today individual psychodynamic psychotherapy, in gross structure very much in the strain of psychoanalytic practice first formed by Freud.
It is important to state that Jung seemed to often see his work as not a complete psychology in itself but as his unique contribution to the field of psychology. Jung claimed late in his career that only for about a third of his patients did he use "Jungian analysis." For another third, Freudian analysis seemed to best suit the patient's needs and for the final third Adlerian analysis was most appropriate. In fact, it seems that most contemporary Jungian clinicians merge a developmentally grounded theory, such as Self psychology or Donald Winnicott's work, with the Jungian theories in order to have a "whole" theoretical repertoire to do actual clinical work.
The "I" or Ego is tremendously important to Jung's clinical work. Jung's theory of etiology of psychopathology could almost be simplified to be stated as a too rigid conscious attitude towards the whole of the psyche. That is, a psychotic episode can be seen from a Jungian perspective as the "rest" of the psyche overwhelming the conscious psyche because the conscious psyche effectively was locking out and repressing the psyche as a whole.
Jung hypothesized a medical basis for schizophrenia that was beyond the understanding of the medical science of his day (and seems to still be beyond present medical science in a satisfactory sense). Twin studies and plenty of clinical material seem to point clearly to a medical basis for schizophrenia. It perhaps can best be said that schizophrenia is both medical and psychological. A medical understanding (again, as yet still lacking) would not change the fact that schizophrenia is lived by those who have it psychologically; that is to say, as theorists and scientists, we may be able to say that schizophrenia happens in genes, brains, and the electrochemical, but for one who has schizophrenia it also happens in their mind and experience. This is to say a purely medical treatment of major mental illness is inadequate, as is a purely psychological treatment of major mental illness.