Schizophrenia is hereditary

What is schizophrenia? The etiology of this psychotic disorder. The role of genetic factors in the development of the disease. Is schizophrenia inherited and through what line? Which population groups are at risk? Association of schizophrenia with other mental illnesses. With these questions, we turned to the Chief Physician of the Health Harmony Medical Center, a psychiatrist, psychiatrist-narcologist and psychotherapist Vladislav Sipovich .

Schizophrenia. What is this disease and how common is it?

Schizophrenia in Greek literally means the splitting of the mind (thought, thinking). Formerly referred to as precox dementia (dementia praecox) or schizophrenia . Now it is considered as a group of endogenous mental disorders, which are characterized by a violation of thought processes, emotional reactions, perception and self-perception, speech and behavior. More than 20 million people on the planet suffer from this severe mental illness.

The most typical manifestations of schizophrenia are as follows:
Hallucinations , most often auditory, when the patient hears other people’s voices in his head. Often they are joined by visual illusions and even sensations of bodily contact with objects that do not actually exist.
Crazy ideas in the form of persistent false beliefs that are not inherent in the environment, not shared by other people and persist despite all evidence to the contrary.
Confabulations are false memories.
Inappropriate, often disorganized behavior – mumbling, laughing for no reason, aimless walking, slovenliness, strange, sloppy appearance, etc.
• Non – adaptive speech in the form of inappropriate, inappropriate, situation and place statements, repetitions, incoherent babble.
Emotional disorders – apathy, imbalance between the emotions experienced and their external manifestations on the face and in gestures.

The danger of schizophrenia is that it leads to a decrease or complete loss of working capacity and learning ability, social dysfunction and early death, which is observed in schizophrenics 2-3 times more often than in healthy people. The latter is explained by the negative association of schizophrenia with diseases of the heart, metabolism, and infectious diseases.

What can cause schizophrenia? To which version is the scientific community more inclined?

The exact origin of schizophrenic disorder is still unknown. Scientists put forward several hypotheses of its development. Among them, the main ones are:
Genetic , according to which schizophrenia is inherited. Partially confirmed by the much greater likelihood of the disease in one of the identical twins, if it is found in the second, as well as in families where blood relatives suffer from this disease. Moreover, the frequency of manifestation of the disease to some extent correlates with the degree of relationship.
Dopamine , linking the occurrence of schizophrenia with a violation of the synthesis and interaction of neurotransmitters dopamine, serotonin, melatonin, produced in the limbic region of the brain. Their increased excretion explains only part of the symptoms, namely delusions and hallucinations, but is in no way associated with a decrease in will and the development of apathy.
With the mismatched work of the right and left hemispheres , violations of the fronto-cerebellar interactions, the neurogenetic theory of the occurrence of the disorder is associated.
Constitutional , based on the psychophysiological characteristics of the individual. For example, men with a gynecomorphic (female type) build and women of a pycnic type (enlarged chest and protruding belly with delicate thin limbs with a weak muscular system) are much more common among schizophrenics.
The infectious theory is rather a tribute to the historical search for the origin of schizophrenia. The idea that a decrease in immunity in chronic infectious diseases is a factor in the development of schizophrenia has not received scientific justification.
The psychoanalytic hypothesis links the occurrence of schizophrenia in people who grew up in families with despotic methods of education, lack of warm relations or their selective manifestation only to one of the children. Also of considerable importance is the ambivalent attitude of parents to the same phenomenon. For example, when a father praises a child for success in a chess game, but internally condemns him for not playing football. The child feels such a split in his assessment and this gives rise to an internal psychological conflict, which can subsequently lead to a schizophrenic disintegration of the personality.
Ecological , recognizing the priority development of schizophrenia in people experiencing mutagenic effects of negative environmental factors in the prenatal period of development. This also includes poor nutrition of the mother during pregnancy, lack of vitamins in her diet.
Evolutionary . Explains schizophrenia as a natural failure in the desire of the nervous system to increase intellectual abilities in a technocratic society. In fact, this means that schizophrenics are people with mutations in the genome, which together form the socio-biological pool of the evolutionary development of intelligence. This slightly fantastic theory allows us to consider schizophrenic disorder as a product of natural selection in a socio-psychological environment.

Although the cause of schizophrenia has not been fully established, its triggers are fairly well known. These include:
• Problems in the family. • Bullying and rot in the team.
• Internal phobias. • Loneliness. • Staying in a chronic stressful situation or severe single stress (loss of a loved one, financial collapse, career destruction, divorce and other negative fundamental changes in a person’s life). • Excessive focus on solving individual problems. • Hormonal changes in adolescence, pregnancy and endocrine disorders. • Self-hypnosis about the presence of a diagnosis of schizophrenia, etc. But no matter what risk factors for the development of schizophrenia exist, the question of whether schizophrenia can be inherited is relevant for people who want to marry and have children, but who have heredity aggravated by schizophrenia. Therefore, consideration of the problem of schizophrenia and heredity deserves special attention.

And yet, is schizophrenia a hereditary disease or an acquired one?

Let’s first define what inheritance is. Heredity is the ability of an organism to pass on to its descendants the characteristics and characteristics of the development of a species. In fact, this is the genetic program of the genus. Please note that not exact copies of the genetic code are transmitted, but their arbitrary combinations with the genome of another organism. On the human level, this means that a new organism arises from a set of 23 maternal and 23 paternal chromosomes. Moreover, chromosomes consist of many genes, each of which is responsible for the formation of individual traits, some of the genes are dominant, while others are recessive. So, the gene responsible for the development of schizophrenia has not yet been identified. It is suggested that he may not be alone, but a whole group that manifests itself as schizophrenia only with a certain interaction with each other.

It is possible that the genes for schizophrenia circulate freely in the human population and appear only when they encounter other genes responsible for starting the pathological process. All this remains to be seen, but the link between schizophrenia and genetics is almost beyond doubt.
Evidence that there is a genetic predisposition to schizophrenia and how schizophrenia is transmitted comes from clinical studies. Determined that:

   1. Relatives of schizophrenics are much more likely to develop schizophrenia than other people. Moreover, the risk is greater for those who are genetically closer to the patient. For example, how schizophrenia is transmitted depending on the degree of kinship is evidenced by the following figures for the probability of developing schizophrenia:
• One of the identical twins, if the second fell ill with schizophrenia – 48%. Such a high percentage is explained by the identity of their chromosome set. • For children born from 2 sick parents – 46%. • In fraternal twins – 17%. • In the presence of 1 sick parent and 1 sick sibling (brother or sister) – 17%.
• At birth from the 1st sick parent – 13%.
• If a person has a sick brother or sister – 9%. • When a sick grandfather or grandmother – 5%. • Nephews of sick uncles or aunts – 4%. • For comparison, the incidence in the general population is 0.7-1.5%. By the way, depending on the region, this figure can vary from 0.24 to 7.1%
2. The risk of getting sick in children from sick parents is almost the same, regardless of whether they were brought up in a biological or foster family. Those. the priority risk factor is still hereditary predisposition, and not the socio-psychological environment.
3. The probability of the disease correlates with the age of the parents. It is known that it rises after they reach 35 years. Perhaps this is due to the accumulation of defective genes, leading to damage to the genome.

To the question of which line schizophrenia is transmitted, there are completely opposite answers. Some authors argue that there is no priority of inheritance depending on gender, others are sure that the disease tends to be inherited more through the female line than through the male. They explain this phenomenon by the presence in the egg of additional genetic material (DNA molecules) contained in the mitochondria of the cytoplasm, and not in the chromosomes of the nucleus. Unlike the genome, it is called a plasmon. Its content in the egg is much greater than in the sperm.

How can one explain the development of schizophrenia in people with uncomplicated heredity?

A very interesting question. In fact, in this case, we are not dealing with the inheritance of genetic damage from parents, but with their occurrence in the prenatal (intrauterine) period of fetal development. Genetic mutations occur under the influence of mutagenic factors at the level of chromosomes or individual genes (point mutations). Moreover, such random mutations are the cause of about half of the cases of genetically determined schizophrenia.

In 2014, a joint study by scientists at the Massachusetts Institute of Technology and Harvard University discovered more than 100 regions of the genome associated with the development of schizophrenia. The data of 29,000 patients with schizophrenia from 30 countries of the world were studied. At the same time, it was possible to establish that people with a genetic predisposition to this disease have an increased expression of the C4 component, which is located on the 4th chromosome and is responsible for the production of one of the immune proteins. Many experts believe that this fact opens up possibilities for establishing the true nature of the disease, but this is only the beginning of a journey that may take several decades.

At the moment, it cannot be determined whether a person with genetic abnormalities will develop schizophrenia or not. Only the following can be asserted:
• The more defective genes, the higher the risk of schizophrenia. • The genes associated with schizophrenia are not specific and may increase the risk of developing other psychotic disorders, such as OCD. • Not the disease itself is inherited, but the program of its metabolic processes. • The manifestation of schizophrenia in people with a genetic predisposition to it does not always occur, its risk increases with chronic stress, acute psychological trauma, as well as with alcoholism, drug addiction. • There are no reliable blood tests and genetic tests to diagnose the disorder and determine whether schizophrenia will be inherited.

In conclusion, I want to say that the inheritance of schizophrenia is complex. It is associated not with one, but with a group of defective genes that act cumulatively or provide certain aspects of the pathological process. Therefore, it is impossible to say with certainty that people who have blood relatives with schizophrenia will get sick themselves or pass the disease on to children is impossible. Yes, they have an increased risk of morbidity, but it is realized depending on external conditions – social, psychological, environmental, as well as biological characteristics of the organism at various periods of its formation and development.

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