This paper describes a possible new scheme for a user with mental health problems to identify his/her own mental state and control it. For that purpose, we propose an indirect biofeedback system which represents physiological information with color and shape, and enables the user to grasp his/her inner state and to proactively change and control it through methods of breathing. Those methods facilitate the user to self-control the autonomic nervous system. Here, we discuss indirect representation and placebo effect.