Radix theory is rooted in the work of the psychiatrist Wilhelm Reich, who in the first half of the 20th century recognised a 'functional identity' between the body and mind. He saw that the mind and body are interrelated and that whatever is happening in one is also reflected in the other. Reich saw the body as a 'frozen history' of our life experiences and therefore a direct link to the unconscious material. Whether psychotherapy takes place primarily at a body level, a mental level or an emotional level that work will impact at all three levels.

One of Reich's fundamental concepts was of the life force which flows through the body and links mind, body and emotion. The founder of Radix, Dr Charles Kelley, an experimental psychologist and forward thinker, developed this concept. He named this life force the Radix, meaning root or source. Kelley saw the radix as the energy flow underlying body, mind and spirit and that working with it means working with all three levels. Kelley also explored the relationship between emotion, vision and perception, bringing an important and unique therapeutic concept and tool to Radix work.

Radix is a process oriented body psychotherapy meaning that therapists connect with the client at the start of each session and develop the session based on what is happening for the client, cognitively, physically and emotionally at that moment. A process orientation facilitates the unfolding of these dimensions by freeing the flow of the radix which in turn develops aliveness, insight, self awareness, discovery, resolution and acceptance.