The entry on Carl Jung from Wikipedia has some good stuff that I wanted to capture for later:

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 word 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 (or complexes) 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. Which 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,” that who separates from the community to some extent to ultimately carry the community further.

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.