A brief synopsis of Jungian
Jungian psychology or complex theory, views the psychological makeup as having a conscious and an unconscious part. These two are inter-connected. From this follows that when something happens in the conscious part there is a reaction in the unconscious as well and vice versa.
What constitutes the conscious? Very simplified you could define the conscious as that what we call reality.
The personal unconscious is made up of repressed memories and experiences and the reactions (sometimes physical) to this repressed content.
We assign meaning in the collective unconscious to how we experience the world. Language, love, death, fear, instincts such as fight or flight; the archetypes are part of the collective unconscious.
Through this method the cause of the problem is uncovered, whether it is conscious or unconscious. At the same time the client is shown how to recognize and interpret the reactions he is experiencing as a result of the problem. By searching for the cause and working through it, a lasting change can be effectuated and the chance of repeating is diminished.
One can call this a personal development process. It can take place autonomously, however through sessions the process is sped up. Eventually it will result in the awareness of personal competencies and blind spots.