The World Health Organization (WHO) defined health in 1948 as not only the absence of disease or infirmity, but also the maintenance of intact physical, mental and social functioning. Maslow proposed ten principles for judging mental health, namely, adequate security, adequate knowledge of oneself and appropriate assessment of one’s abilities; realistic goals in life; ability to maintain contact with the real environment; ability to maintain integrity and harmony of personality; ability to learn from experience; ability to maintain good interpersonal relationships; moderate emotional expression as well as control; ability to make limited individuality without violating social norms; and the ability to appropriately meet basic personal requirements without violating social norms. A famous Chinese psychology professor interpreted mental health based on Chinese culture and proposed the “16-word standard for mental health”: knowing oneself and one’s opponent, reacting appropriately, being truthful and harmonious, and being happy and aggressive. In general, mental health does not really mean “the absence of psychological problems or mental illnesses”, but “a state of mind that develops positively on the basis of the absence of psychological problems or mental illnesses”. Some books define mental health as “a consistently productive and satisfying psychological state”, but this standard describes a perfect psychological state, which few people are in all the time.