Is schizophrenia a hereditary disease?

Schizophrenia is a mental illness in which a person’s perception of reality is impaired, the nervous system is unstable, behavior is affective, consciousness is impaired, which negatively affects thinking.
Such people are not weak-minded, but are unable to live fully in society, have problems with adaptation, communication, etc. Many people are concerned about the reasons for the appearance of such a pathology, among which there is this one: “Is schizophrenia inherited?” People, knowing that many diseases are transmitted from parents to children using genes, are very afraid that they or their children will get schizophrenia from one of their relatives.

For a long time, families in which there were mentally ill people were considered cursed, and their sins and evil spirits were blamed for this. They did not want to get involved with members of such families or enter into marriage relationships, fearing for the mental health of their future offspring.

Unfortunately, such “denseness” is still alive, although now, when society is more enlightened, they say: “You can’t fight against genes”! This opinion is fueled by numerous articles from the Internet, pseudo-scientific programs on TV and even films.

Adherents of such knowledge, having gained scholarship from the above-mentioned sources, are absolutely sure that schizophrenia is transmitted exclusively at the genetic level, but strictly through a generation, that is, from grandparents. But there are no exact statements about who takes more risks, girls or boys.

Let's try to find the truth.

Theories

According to scientists, there are several hypotheses for the development of schizophrenia, and, as they say, each of them has not been accurately confirmed:

1. Dopamine. Human mental activity is carried out through the production in the brain of the mediators dopamine, serotonin, melatonin, and their interaction. If dopamine receptors in the limbic region experience increased stimulation, then the individual experiences hallucinations and delusions - clear symptoms of schizophrenia.
2. Constitutional. This refers to the peculiarities of the psychophysical state of a person.
3. Infectious. There is an opinion that chronic viral diseases, streptococcus, tuberculosis bacillus, staphylococcus reduce immunity and thereby give impetus to the development of mental disorders.
4. Neurogenetic. A defect in the corpus callosum in the brain disrupts the coordination between the left and right hemispheres. This also includes the rupture of fronto-cerebellar connections.
5. Ecological. The negative impact of environmental pollution on the formation of the fetus and the lack of vitamins during this period.
6. Psychoanalytic. Raising a child by an oppressive father, a harsh mother, a negative, cold atmosphere in the family.
7. Evolutionary. Nature, under the influence of the increase in the intellectual abilities of people and the technocratic development of society, tries to adjust the functioning of the brain to them, but fails.
8. Brain injuries.
9. Genetic. In families whose parents or ancestors (grandparents, great-great relatives, and so on), the appearance of descendants with schizophrenia is most likely.

Experts believe that all these factors can cause the development of schizophrenia. In addition to them, drug addiction, alcoholism, and acute stress should not be discounted.

Diagnostics

At different stages, schizophrenia manifests symptoms in a range of emotions from baby talk and delusions with hallucinations to suicide attempts. It is necessary to conduct a medical examination to determine the exact clinical picture. Anamnesis is collected based on detailed questions about the patient and his relatives. The doctor will conduct a test for schizophrenia to determine the diagnosis. We are talking about a neurotest that shows immune blood parameters. Based on them, a decision is made on the final diagnosis and its severity. If necessary, the patient may be prescribed an MRI of the brain. Correctly selected treatment for schizophrenia has good results. In 50% it is possible to achieve remission, and 25% of patients completely get rid of the diagnosis, provided that the forms of schizophrenia can be corrected.

Pros and cons"

Scientists have long been deeply engaged in searching for a hereditary factor in the transmission of the schizophrenia gene, but they cannot provide any precise evidence.

There is a story about how they found as many as 74 genes for this mental illness, but they were never presented to the medical community.

It is impossible to establish a diagnosis based on the results of genetic tests or blood, although there are charlatans who claim to have mastery of such a technique.

Researchers have identified a set of genes that disrupt brain function, but there is no evidence that they are responsible for the development of schizophrenia.

The hereditary factor is also refuted by the fact that in the genealogy of quite a large number of patients there are no relatives suffering from this pathology. However, 30% of patients still have them.

Let's take a look at the statistics of diagnosed schizophrenics:

• 1% – a disease that appeared for the first time in the family;
• 2% – a nephew, uncle/aunt, cousin/cousin is sick;
• 5% – great-grandfather/great-grandmother had the disease;
• 5% – a sibling suffers from schizophrenia;
• 10% – the same sister or brother, but relatives of the 1st–3rd line are added to them have mental disorders;
• 10% – grandmother/grandfather is sick;
• 20% – schizophrenia in mom or dad.

As can be seen from the figures, the risk of developing this mental illness if you have relevant relatives is quite high, especially if they are close. But this does not 100% indicate that it will definitely manifest itself in the next generation. By the way, the situation with type II diabetes mellitus and some types of cancer is much more deplorable.

Is schizophrenia inherited from mother or father? Psychiatrists and scientists say that no direct pattern of transmission of the disease through the female or male line has been identified. And in general, they still do not classify schizophrenia as a hereditary disease.

However, experts warn couples planning a child: if one of the future parents or their relatives has this mental disorder, then it is advisable to consult a psychiatrist. They will undergo a thorough examination and be warned of possible risks.

Heredity risks

Mendel made a great contribution to the study of heredity by conducting experiments on peas. Later, studies on Drosophila flies were summarized, confirming Mendel's laws. With people things are much more complicated. In humans, population growth is noticeably lower than in peas or flies. To fully compile a picture of the disease, it is necessary to conduct examinations of the child, parents, grandparents, brothers, sisters, etc. Such research extends over more than one generation of geneticists. From the data obtained, when constructing a complete family tree, a certain percentage of inheritance of schizophrenia can be calculated.

When calculating the incidence of diseases, non-standard situations were documented. For example, a grandchild develops schizophrenia earlier than a grandparent. If a patient has schizophrenia, it is possible to determine the % probability of its development in a relative. If a person suffers from schizophrenia, then the percentage of the disease for relatives is as follows:

• Aunt and uncle – 2%.
• Nephews – 4%.
• Grandchildren – 5%.
• Parents – 6%.
• Children – 13%.
• Twin children: identical twins - 48%; fraternal twins - 17%.

The percentage probability increases sharply in children if both parents have schizophrenia.

Time bomb?

And this is where the fun begins. It is impossible to detect the presence of a “wrong” gene using genetic testing. In a specialized consultation, specialists will describe the client’s risks, and by examining the fetus in the expectant mother’s womb, they can indicate the presence or absence of a defect.

However, there are diseases caused by several genes, of which there are from two to ten. Let's look at this situation using the example of rheumatism. Is there any heredity for it? No! The whole point is this: to get sick, it is not enough to be a carrier of rheumatism genes; you also need to catch group A hemolytic streptococcus. That is, this is simply a feature of the immune system, which is easily affected.

What is the situation with schizophrenics if they have a different set of “damaged” genes? This means that for some it is, for example, ABC, for others it is AB, and for others it is only C and the like. There is one thing in common: their functions affect brain development, preventing the process from proceeding normally. And the more such suspicious genes there are, the higher the likelihood of developing a mental disorder. And one more thing: the risk is increased by 16 times by defects in genes on the third chromosome, and by 8 times on the sixteenth.

Despite many years of efforts by geneticists, they cannot create a profile of a schizophrenic. That is, there is no test yet that can answer the question of the possibility of getting sick.

As already mentioned, in order for “bad” genes to manifest themselves, they need some kind of push. If there is none, then the carrier, having them in large quantities, will not get sick. Exactly what external factors these should be is unknown.

Let's take identical twins, who have the same everything, including genes. But one of them has schizophrenia, and the other is completely healthy, and his risk of getting sick is 46%. Why not 100%, you ask? The answer is: some of the patient’s genes were locked by a methyl group, and because of this “lock,” they stopped functioning, and brain development was disrupted.

Where did this group come from? It is unknown, but it has been suggested that the influenza virus is to blame, since the boys’ mother, while pregnant, had it.

According to current data, the risk of schizophrenia in a child due to influenza suffered by the expectant mother increases by 1.5-7 times. However, this is not due specifically to the virus, but to an overly strong immune reaction of the woman’s body, which increased the amount of interleukin-8. But you need to know: not all such cases can provoke the development of mental illness in the offspring.

How can we explain the development of schizophrenia in people with no family history?

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 approximately half of the cases of genetically determined schizophrenia.

In 2014, as a result of a joint study by scientists at the Massachusetts Institute of Technology and Harvard University, more than 100 regions of the genome were discovered that are associated with the development of schizophrenia. Data from 29,000 schizophrenic patients from 30 countries 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, located on the 4th chromosome and responsible for the production of one of the immune proteins. Many experts believe that this fact opens up the possibility of 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 is not possible to determine whether a person with genetic abnormalities will develop schizophrenia or not. We can only say the following: • The more defective genes, the higher the risk of schizophrenia. • Genes associated with schizophrenia are not specific and may increase the risk of developing other psychotic disorders, particularly OCD. • It is not the disease itself that 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 and drug addiction. • There are no reliable blood tests or genetic testing to diagnose the disorder or determine whether schizophrenia will be inherited.

In conclusion, I would like 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 individual 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 their children. 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 body during various periods of its formation and development.

Nature games

There is a misconception that the absence of “schizophrenic genes,” or, more correctly, those responsible for brain development, is an exact guarantee of not getting sick with this terrible mental disorder. But it was not there! 10% of patients have a history of such ancestors being completely absent in the foreseeable past. But, what is sad for every person, genes can mutate, and no one knows what this could threaten us with.

“Genes of the mind,” let’s call them that, are very sensitive and, easily exposed to the influence of the external environment, change. On the one hand, this is good - thanks to this property, man evolved, but on the other hand, as we see, it is completely bad.

And once again: it is impossible to predict that an individual with a defective genome will give birth to a sick child. Just like the fact that healthy parents have completely healthy parents. Alas…

How to make an appointment with a psychiatrist at JSC “Medicine” (clinic of academician Roitberg)

Anyone who has been diagnosed with schizophrenia needs psychological help. This is a normal human need to strive to return to normal life. Our clinic treats the delicate problems of patients with understanding. At the appointment, a psychiatrist will help you understand the essence of schizophrenia, find a way out of the situation and support you on the path to recovery.

You can make an appointment with a doctor on the website using a special form or by calling +7 (495) 775-73-60. The clinic is located within walking distance from the Mayakovskaya metro station in the center of Moscow: 2nd Tverskoy-Yamskaya lane, 10.

Symptoms of schizophrenia (just in case)

First of all, let us reassure those who are tense: this mental illness can be treated quite successfully, especially if it can be stopped in the initial stage, and if the therapy was carried out by an experienced psychiatrist. Former patients who have overcome schizophrenia graduate from higher educational institutions, get prestigious jobs and good positions, start families, in general, their lives are full.

Experts determine the presence of the disease by these three types of symptoms that last for a month:

• the presence of extraneous voices in the head, hallucinations, delusional thoughts, which the patient himself considers brilliant;
• disorder of cognitive abilities - thinking, perception, coherence of speech, attention, etc.;
• lack of desire, motivation to do something, will, the onset of apathy.

It is difficult for a schizophrenic to communicate with other people; he experiences difficulties in society. No events interest him, he loses interest in life. Such a person can either freeze in an unnatural position or become suddenly aroused.

Timely consultation with a doctor allows you to relieve these symptoms with the help of medications and psychotherapy. There are now a huge number of treatment methods, so it is important to see an experienced specialist.

It should be kept in mind that with age, the likelihood of developing schizophrenia decreases. According to statistics this is:

• 10–20 years – 17%;
• 20–30 years old – 39%;
• 30–40 years old – 26%
• 40–50 years old – 14%.

Experts offer advice on preventing schizophrenia to people who are particularly concerned about developing the disease. They are recommended:

• do not drink alcohol or drugs, do not smoke;
• play sports, be active;
• treats life correctly, does not keep problems inside, does not become isolated. It is advisable to have your own psychologist, so that in case of emotional distress or indifference, you can get his advice;
• be aware that a burdened heredity is not the end of the world at all, and nothing terrible may happen.

Treatment

The first signs of schizophrenia are the ideal time to start therapy. In most cases, this does not work out because the symptoms are ignored or mistaken for other pathological conditions. If the test for schizophrenia confirms the diagnosis, the doctor will prescribe appropriate treatment. If acute symptoms occur, drug correction is recommended. This mainly applies to the following conditions: depression, anxiety, sleep problems, severe apathy, thinking disorders. Schizophrenia in men and women, if the treatment plan is followed, has a positive prognosis. For this purpose, psychotherapy is also used and social rehabilitation is carried out. In the process of treatment, it is necessary to ensure that the signs of schizophrenia in the negative group decrease in severity. In the future, it is important to maintain the condition to avoid relapses.