Why do blind from birth people do not suffer from schizophrenia?

In fact, we know very little about schizophrenia. I realized this when I watched a lecture by Professor of neurobiology Stanford University Robert Sapolsky in which a scientist spoke in detail about the disease. So if you don’t know what to look for during the quarantine, the lectures of Dr. Sapolsky called “Biology of human behavior” is on YouTube in Russian. But back to the mysteries of schizophrenia, and there are now a lot. So, in the history of the study of schizophrenia there is a curious fact: blind from birth people can’t get sick with schizophrenia. At least until now there was not a single such case. For the past 60 years, scientists around the world wrote about it, browsing the database, and unsuccessfully searched for the man blind from birth person with schizophrenia. To understand why this phenomenon concerned scientists, let’s figure out what are schizophrenia and congenital blindness, as well as what relationship exists (and is there) between them.

Congenital blindness is a medical term that means complete absence of vision since birth. Causes of congenital blindness can be a lot, but in 2012 scientists discovered a gene whose activity leads to the development of this disease. The study is published in the journal Nature Genetics.

Schizophrenia is a severe mental disease characterized by violation of coherence of mental processes, and decline of mental activity. Long considered exclusively a mental illness and only recently, scientists were able to learn more about how the brain works for such people. So, a few years ago, scientists discovered that in the brains of patients with schizophrenia observed extensive damage to the structure of the white matter.

White matter is tissue that consists of nerve fibers – axonsthat provide the link between neurons in different areas of the brain. Needless to say, that the coupling between neurons is extremely important for the normal functioning of the nervous system.

The symptoms of schizophrenia may be of varying severity, but in General patients present disintegration of thought processes and emotional reactions. The most frequent symptoms of schizophrenia are auditory and visual hallucinations, as well as fantastic and paranoid delusions. It is noteworthy that schizophrenia is a hereditary disease that is very difficult to understand from a genetic and evolutionary perspective. However, in recent years, scientists have been major advances in the study of the genetics of this disease, and artificial intelligence have learned to recognize its early symptoms.

How are schizophrenia and blindness?

The fact that there is not a single schizophrenic person, blind from birth suggests that congenital blindness somehow protects a person from schizophrenia. If you lost your eyesight at a later period of life and in the family have relatives with schizophrenia, the chances of getting sick increase significantly. In fact, if a healthy person for several days to deprive of sight, then he might be hallucinating. As you know, people with schizophrenia often report problems with vision and blurred vision and visual anomalies are increasingly celebrated as a harbinger of schizophrenia. But whether this data can help in the search for solving the mystery of schizophrenia and its treatment?

One of the most important functions of the brain is the ability to make predictions about the world. No other animal on Earth can do something like this. Our brain creates models of reality that predict and model what happens in reality, not perceiving the world in real time. In this vision,not obviously plays in predicting an important role, as it gives a lot of information about the surrounding world and connects the other senses, such as sound and touch. Thus, if a person’s vision distorted, the world model constructed by the brain reset. For this reason, the brain makes more and more predictions to explain these discrepancies, ultimately changing the entire model. However, if you do not see, can not feel about the visual presentation (hallucinations). If blind from birth people can’t use sight to build their model of the world, they rely on other senses.

As I write in the work devoted to this phenomenon, the authors of the new study, the idea that they are trying to understand, is that in people blind from birth should be responsible for the stable representation of the world. This stability is, in a sense, protects them from mistakes and false conclusions, which are observed in patients with schizophrenia people. Learn more about the study on pages of the scientific journal Schizophrenia Bulletin.