To determine whether a particular person has a mental illness, generally analyze the following three aspects: 1. Vertical comparison, that is, comparison with past consistent performance, to see whether their mental activities, mental activities have significantly changed; 2. Horizontal comparison, that is, comparison with most normal people’s mental activities, mental activities, to see whether their mental activities, mental activities and other normal people have The obvious difference. Whether the duration of a certain mental activity exceeds the general limit, such as depression lasting more than two weeks; 3. Whether it is consistent with the real environment, attention needs to be paid to the specific analysis and judgment of his mental activity in the context of the person’s psychological background, and the environment at that time. In clinical practice, the above three aspects are needed to assess the mental outlook of the patient or visitor to judge the presence of mental illness.