What is the disease

In the daily life of firewood, rice, oil and salt, we eat grains and cereals, and we will definitely get sick. Various symptoms represent different diseases. If we only say disease, it should refer to the general term for all diseases. We all know only each disease and each type of disease, but we don’t know what disease refers to. If we only say that so-and-so has a disease, we will definitely ask one more question: what disease is it?

Diseases that deviate from the normal form and function of the human body, like health, can be defined differently when examined from different perspectives. The most commonly used definition is "deviation from the normal form and function of the human body." Modern medicine has measured various biological parameters of the human body (including intelligence), and their values ​​generally obey the normal distribution law in statistics, that is, a mean and the range of 95% of healthy individuals can be calculated. This range is usually called "normal". If it is outside this range, too high or too low, it is "abnormal" and disease falls into the abnormal range. In many cases, this definition is applicable, such as typhoid fever can be manifested as an increase in body temperature and "typhoid hemagglutinin" (antibodies) in the blood over a certain period of time.

However, there are large individual differences and biological variations in normal people, and sometimes this definition does not apply. For example, the size of a normal human heart falls within a certain range, and many diseases can cause the heart to enlarge. But for athletes, a heart that is larger than normal and accompanied by bradycardia (as slow as 40 beats per minute) is not pathological; this deviation from the normal value is due to individual differences. In terms of mental health, those whose IQ far exceeds that of their peers are geniuses, not patients. Some people define disease in terms of function or adaptability, believing that impaired function and disruption of the ability to coordinate with the environment are manifestations of disease. This can avoid misclassifying individual differences and biological variations in normal people as diseases. Sickle cell anemia, in which symptoms only appear when there is a lack of oxygen, is a defect in adaptive ability.

For many mental patients, it is particularly necessary to examine their ability to coordinate with the environment. However, poor adaptive function is not necessarily a disease. For example, a mental worker who lacks physical activity for a long time cannot adapt to physical activities that ordinary people can do, and suffers from back pain when slightly tired. This is not necessarily a disease. Therefore, some people suggest adding a "disease-free state" between health and disease. So far, there is no satisfactory definition of disease.

The above is a relatively written definition of disease. Through understanding the above definition, we know that there is no exact definition of disease so far. We just know that as long as the body is no longer in a healthy state, it can be said to be suffering from a certain disease. There are tens of millions of types of diseases, and we do not know and understand them all. It is enough for us to understand a few basic concepts of disease.