This article proposes a new theoretical and methodological approach to the study of the therapeutic environment. The theoretical concept is based on the field theory in the Gestalt-approach, the principles of Ecopsychology, the individual elements of the field theory of K. Lewin and the theory of concurrent processes. The processual paradigm considers any action in the medical environment as a derivative of the situation of interpersonal interaction, emphasizing the dynamic and interdependent nature of the observed phenomena. A new approach to the study allowed the author to give a new definition of adherence to treatment in the medical environment and to allocate its types, to offer in accordance with the criteria of efficiency of treatment and associate them with levels of provision polyprofessional medical care. This approach can be used in the study of any therapeutic environment, taking into account the processual nature of the studied phenomena.