The promotion of mental health for the primary prevention of mental disorders is one of the most important tasks in psychiatry-related fields. Although the current primary measures to promote personal mental health are "stress management" and "development of knowledge about mental disorders", these measures are directed at preventing mental disorders. Therefore, it is doubtful whether they are adequate for promoting personal mental health, considering that mental health is not just the absence of mental disorder. In order to take adequate measures to promote mental health, there must be a "fundamental theory of mental health" that is able to answer the following two fundamental questions: (1) what does it mean to be mentally healthy and (2) how we can achieve mental health? I think that psychotherapy, which psychiatrists employ in psychiatric practice, implicitly includes the answers to these two fundamental questions. Based on this idea, I constructed an innovative and useful "fundamental theory of mental health" from different psychotherapies. In the process of constructing this theory, methods and findings from the "philosophy of mind", which is a branch of philosophy that studies the nature of the mind, greatly clarified the views on the human mind related to the theory of mental health. I herein introduce my research progress as an example.(1) I extracted insights into what it means to be mentally healthy and how we can achieve mental health from Morita Therapy, which is an original Japanese psychotherapy.(2) I constructed a theory called "Natural Humanics" after clarifying the views on the human mind,(3) and I am developing and practicing a new mental health education system based on this theory.
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