At the intersection of philosophy and psychology stand a group of thinkers who try to distill the main motivations of what moves an individual. These thinkers believe that the prime motivation of what moves a person - whether he knows it or not - is the power of this one motivation. And this prime motivation is always couched as "will to...."
Anything and everything else a person wants are secondary or reactionary needs to the demands of the prime motivation. According to these theorists if you dig deep enough everything positive and negative, neurotic and healthy, can be found in this prime motivation.
There are many theories out there today, but the main ones are:
Will to Pleasure (aka the Pleasure Principle) - Freud
Will to Live - Schopenhauer
Will to Power - Nietzsche/Adler
Will to Relationships - Yalom
Will to Meaning - Frankl
To Freud and Adler, the purpose of therapy is to find the prime motivations through the subconscious and find how societal, family or other external constructs create conflict to the prime motivation (however the person defines "pleasure" or "power"), and thus create psychosis.
Yalom, believing relationships are the prime mover to what drives people, believes in a therapy that simply provides an intimate relationship, famously saying that "the relationship IS the therapy". Perhaps a better phrase for Yalom is "Will to intimacy". By finding intimacy through therapy, the patient finds what he is looking for, and learns through the process how to find it out in the real world.
Frankl, taking a more classical, almost Platonic view, believes the drive to find meaning in life is the prime motivator of people. In his theory, some can "will" to suffer, if that suffering provides meaning to one's life. His therapy would be familiar to pastors or Rabbis trying to help individuals tease out the reasons of their existence.
Which one do you think is the right one? Or do you have one of your own?