Schizophrenia is one of the most complex psychiatric pathologies, the complexity of which is due to its unclear etiology and unpredictable course. The exact causes of schizophrenia are unknown. Scientists speak only about the factors that increase the likelihood of its development. Heredity is one of them. Let’s find out if schizophrenia is hereditary and how it happens.


Opinions of scientists

In the literature on schizophrenia, there is a variety of data regarding the causes of schizophrenia. There are even separate theories in which scientists conduct their research and try to confirm or refute one or another hypothesis. Some of them are:

  • Dopamine. Increased dopamine, melatonin, and serotonin production lead to delirium and hallucinations.
  • Infectious. Chronic viral diseases and streptococcal, staphylococcal, and tuberculosis infections reduce immunity and cause mental disorders.
  • Neurogenetic. A defect in the corpus callosum, which connects the left and right hemispheres, leads to a violation of the collective work of the brain.
  • Environmental. Environmental pollution negatively affects the embryo’s development, causes vitamin deficiencies, and ultimately increases the likelihood of psychiatric pathologies.
  • Psychoanalytic. A bad relationship with an oppressive father or strict mother, a cold atmosphere in the family, etc., can lead to the emergence of the disease.
  • Evolutionary. An increase in intellectual abilities due to technological progress does not coincide with the brain’s natural abilities. Nature tries to adapt to changes but sometimes fails.
  • Traumatic. Mental disorders can be caused by various types of trauma, including postpartum and surgery.
  • Genetic. If there is at least one person with schizophrenia in the family. The likelihood of others developing it increases.
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That said, there may be disagreement within each of the theories listed. Some scientists claim the existence of 74 or even 100 genes responsible for schizophrenia. Other researchers are more reserved in their conclusions, believing that the exact data on this issue has yet to be discovered.

Medics have found a set of genes that can affect brain function. But making a direct link between them and schizophrenia is difficult enough. It is not a case where researchers have taken DNA, studied it, decomposed the genes into dominant and recessive genes, and found the exact chain that affected the development of the disease. In any case, the conclusion of genetic causation would be a guess, not an exact scientific fact.

  • Today there are three main approaches to the study of hereditary factors in schizophrenia:
  • Genetic, which is necessary to study differences in gene structure.
  • Pharmacogenetics allows proper therapy use, prescription of appropriate drugs, and reduction of side effects.
  • Genetic, aimed at studying the etiology of the disease.

In addition to studies on the genetics of schizophrenia, which do not always confirm the hypotheses, scientists have statistics that show that they should study genetic factors without fail.


Schizophrenia Inherited


Statistical information

Schizophrenia is generally diagnosed in 0.5 to 1% of people. One out of 100 people will be affected by the disease. These are the risks and percentages of schizophrenia.

  • 1% – the first case in the family.
  • 2% – an uncle/aunt, nephew or cousin/sister had the disease.
  • 5% – great-grandmother or great-grandfather had the disease.
  • 5% – a sibling suffers from the pathology.
  • 10% – a brother, sister, or relatives in the 1st-3rd line were sick.
  • 10% – grandmother or grandfather was diagnosed.
  • 20% – dad or mom has the pathology.

At the same time, the probability of a child from two schizophrenic parents developing the pathology is 45-60%. Among twins, the statistics are as follows: 13-17% for dizygotic and 47-48% for monozygotic.

As one can see, the closer the degree of relationship, the greater the risk of the disease. However, it is incorrect to state for 100% that a child of two parents with schizophrenia will suffer from this pathology. There is a possibility, but not as high as many people believe.


Relatives of the affected patients

Current genetic research shows that specific pathologies are genetically predetermined and many aspects of personality such as excessive anxiety or calmness, shyness, and hypersensitivity. Can also inherit a tendency toward aggression, wariness, sensitivity to criticism, and the ability to react to new circumstances

Similar data allows studies of identical twins raised in different environments, even with different upbringing, common traits of character, and temperament. And this even applies to the love of risk and adventure.

Genetic factors play an essential role in pathologies such as schizophrenia and autism. It is also subject to scrutiny in analyzing various affective and hyperactivity disorders. In doing so, scientists find behavioral, biochemical, and immunological similarities.

It means that blood composition, lymphocyte counts, and other biological indicators in patients with schizophrenia largely coincide with similar data in their relatives, even if the latter do not have psychiatric disorders.

Researchers suggest considering three categories of relatives who have patients with schizophrenia in their family:

  • People with schizoid traits – withdrawal, loneliness, and a focus on the inner rather than the outer world.
  • Individuals with schizoid traits and an apparent emotional defect
  • Individuals with schizoid features with affective disorders (bipolar phase changes, seasonal depressions, etc.).

Statistics show that about 20-30% of relatives of people with first-degree schizophrenia complain of specific symptoms. In this case, there is no diagnosis, so they speak of so-called “spectrum disorders.” The symptomatology is relatively weak and is more indicative of withdrawal, vulnerability, and low emotional intelligence. They are also observed in many people with schizophrenia, especially before the onset of a seizure.


Cognitive abilities of patients’ relatives

Among the relatives of patients with schizophrenia, as far as the cognitive sphere is concerned, the following regularities are observed:

  • Altered psychomotor speed;
  • Impairment of visual and short-term verbal memory;
  • Instability of attention;
  • The unusualness of the formation of judgments (abstractness);
  • Difficulties in the organization of the plan of action;
  • Difficulty in copying images.

But this does not apply to all relatives. Most people either do not have these traits or compensate for them with sufficient intellectual activity. However, it is wrong to exclude the presence of these patterns in the analysis.


Brain structural changes

Another type of research concerns structural and functional changes in the brain, which are registered in relatives of patients with schizophrenia. In particular, we are talking about such features:

  • Enlargement of the third and lateral ventricles.
  • Enlargement of the thalamus.
  • Impairment of the motility of the eye muscles.

These findings are obtained through implantation of electrodes, antisaccade tests (eye movements behind an object), electrophysiological and other studies.


The influence of the male line

In men, schizophrenia appears earlier and is accompanied by more obvious signs. Therefore, doctors need to understand whether it is inherited more often from the father than from the mother. In general, these patterns are observed:

  • Men are prone to become ill with psychiatric pathologies as early as childhood or adolescence.
  • Such illnesses in them progress rapidly.
  • A minor factor may trigger the development of an illness or an attack.
  • Men are, in principle, more susceptible to neuropsychological overload.

However, practice shows that despite all these facts, schizophrenia is often inherited specifically from women. But because of the severity of symptoms, there is an impression that men have this psychosis more often. It leads to a stereotype about the male nature of the disease. But in reality, women are no less ill with it. Just the first signs appear later – after about six years.

In addition, other factors increase the risk of developing schizophrenia. Among these are alcoholism and drug addiction, which are more often observed in the male sex. Men are also less likely to go to doctors; therefore, the pathology progresses for a long time without any medical intervention.

All of these factors increase the risk of developing mental illness. However, this does not mean it is passed on from father to son. However, should not be excluded even this possibility. It is just that the mechanism of transmission of the disease remains unknown.


The influence of the female line

The risk of getting schizophrenia through the female line, that is, from the mother, is five times higher than from the father. But the transmission mechanism, as in all other situations, is unknown. Scientists have only specific clinical cases. Therefore, it is impossible to say whether a woman with schizophrenia will have schizophrenic children. However, excluding other risks is necessary to decrease the probability percentage.

An assumption is that a woman may be carriers of a chromosomal mutation that may cause her child to develop schizophrenia. However, she may not have the disease herself. For example, this is often the case with color blindness, which is often found in men, but women often carry the gene for this disorder.

An infectious or respiratory disease suffered by the mother while carrying the fetus may be a trigger for the development of schizophrenia. Also, during this period, toxemia and alcohol consumption is dangerous. These, in principle, hurt the embryo. It turns out that there is also a risk of brain damage, which can later cause schizophrenia.

In this context, it is essential to consider the social causes of the pathology, which are related to the woman. We are talking about the problematic conditions of the child’s development and the lack of complete care for the child. But in any case, schizophrenia becomes a consequence of many causes, which should include biochemical pathologies, organic brain lesions, etc.


How to influence genes

So, the inheritance of the pathology in question is an assumption that is not exactly confirmed by scientific data. Genetic conditioning is considered to be one of the triggering factors. To date, no identified gene exactly leads to this disease. In most cases, we are talking about a set of genes that hypothetically could be a trigger for the development of schizophrenia.

But is the predisposition, when a relative has a history of such a diagnosis, a “time bomb”? Should a person whose grandmother, mother, or sister has suffered from this illness constantly have their mental health checked?

Consider the example of alcoholism. No doctor will tell you the exact causes either. Even though many scientists claim to have discovered the gene, there is always more than one factor. Even if this is true, it is not possible to influence it.

Moreover, alcoholism is almost 50% caused by the environment. If there is also a genetic predisposition, this percentage becomes slightly higher. But to influence this, i.e., to prevent the disease, is possible only through social factors: not to visit places where people drink a lot, lead a healthy lifestyle, come for psychological consultations, and so on.

In almost all cases, there must be a trigger for the faulty genes to manifest themselves. If there is no such trigger, a person with a large set of genes hypothetically causing schizophrenia may live a quiet life without any hint of psychiatric disorder.

Here is another example directly related to the disease in question. Imagine identical twins with identical genes. If one of them gets schizophrenia, the risk of the other one getting it is less than 50%. It means that other causes have nothing to do with heredity.


Absence of predisposition

Around 10% of schizophrenia patients have no predisposition. It is unlikely that any of the family members can identify it. Doctors can examine all relatives, and the results will be available. In principle, it is unlikely to detect signs of mental disorders.

It means that people who hypothetically should never get sick, according to proponents of the genetic theory, are also at risk for the pathology. And the 10% of patients the statistics tell us about is relatively high.


Other risk factors

People who have a relative who has schizophrenia are advised to rule out other risk factors. If you are a carrier of genes that cause schizophrenia, it is worthwhile to be on the safe side and take all possible measures to prevent the pathology. Some risk factors have been described above in the theories and hypotheses section. Let’s list the psychological and social causes. Among the first ones:

  • Insularity concentrates on one’s inner world;
  • Passivity, suspiciousness, and stubbornness;
  • A tendency to extensive reasoning;
  • Difficulty in formulating thoughts;
  • Inadequacy of emotional reactions.

This last point refers to situations in which unimportant events strongly affect the person, and serious tragedies do not provoke an emotional response. These symptoms can indicate a person is prone to schizophrenia. If they are present in a child, they should be seen by a psychologist or psychiatrist.

See Also: Color Dreams and Schizophrenia – is there a relationship?

Social factors, which are understood to be environmental influences, include:

  • Uncomfortable living conditions – overcrowding in the city, many people in the apartment. All of this leads to a high level of stress;
  • Social status. If he is low and the person does not have a good job and earnings, the likelihood of psychosis increases;
  • Negative relationships in the family. We discuss conflicts, excessive hostility, suspicions, constant criticism, etc.

The reasons for schizophrenia can be listed almost endlessly: alcoholism, drug addiction, sexual or other violence, trauma, etc. In addition, it is worth understanding that this pathology is diverse. It takes various forms – seizure-like, paranoid, lazy, etc. Some patients with this diagnosis live an ordinary life, while others die or become incapacitated.

However, it is advisable to begin treatment as soon as possible in all cases. It is essential to recognize the signs early. A significant role in this is given to relatives, whose efforts often succeed in bringing the person to the first examination.



The symptoms are determined by the type and form of the disease. However, several signs are characteristic of almost all varieties of this pathology:

  • The openness of thoughts. It seems to the person that all his thoughts are available to others.
  • Problems with thinking. People with schizophrenia are often prone to lengthy reasoning. They constantly stumble, get confused, and cannot fully articulate what they want to convey to others.
  • Delirium. It seems to the patient that his thoughts, actions, and feelings are controlled by someone else.
  • Hallucinations and pseudo-hallucinations. The latter differs from the former because the person does not identify the existing objects’ images, voices, sounds, and smells.
  • Emotional disorders. As a rule, patients are prone to apathy and pathological experiences.

You may also notice less apparent signs. These are known as negative symptoms. They indicate a decline in mental activity.

  • Lack of initiative;
  • Decreased memory and attention;
  • Rapid fatigue;
  • Loss of interest in anything;
  • Lethargy or lack of facial expressions;
  • Withdrawal and a tendency to loneliness;
  • Inability to enjoy life.
See Also: Color Dreams and Schizophrenia – is there a relationship?

In adults, communication abilities are lost, professional unsuitability, and suicidal behavior. Children can observe the following signs of the disease:

  • Unexplained fear. The child refuses to go into a room or approach a place, screams, balks, and throws tantrums for no apparent reason. It is not uncommon for children with this diagnosis to tell stories about scary creatures and even show the places where they are.
  • Strange fantasies. During stories about movie or comic book characters, the child is so immersed in his role that he cannot escape it for a long time.
  • The decline in intelligence. He loses his attention, forgets new information, and has a decrease in school performance.
  • Strange actions. The child constantly looks around, listens, or speaks in whispers. It is possible that he hears voices and does not realize they are only in his head.
  • Inadequate emotions. Expresses them in a way that is not appropriate for the situation. He may cry, laugh, be happy, or grieve when there is no objective reason.
  • Manifestations of cruelty. The child becomes more aggressive, communicates less often with peers, and tends to abuse animals or toys.

Some of these signs, in one form or another, can be found in healthy children with poor parenting. It is essential not to leave them unattended, as schizophrenia that started early leads to more severe consequences than the same pathology that arose in an adult.


When it shows itself

Medical practice shows that the risk of developing schizophrenia decreases with age. According to statistics, the disease manifests itself with the following frequency:

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

More specifically, the risk gets higher and higher at first. It continues until about 30 years of age. Subsequently, the likelihood of falling ill is much less. However, it can manifest a few years after birth and in old age. The risk is lower, but it still exists.



So, schizophrenia can be congenital (hereditary) and acquired. No doctor will be able to tell you the exact cause. If you have a genetic predisposition, you should not be afraid of the disease all your life. However, other risk factors should be removed if possible.

Schizophrenia is not entirely curable. But this does not mean that you can leave it untreated or, on the contrary, despair. In many cases, doctors can permanently or for years stop the symptoms of the disease. The main thing is to start treatment immediately to prevent severe damage to the personality or its destruction.

Science does not stand still. Perhaps in 10-20 years, scientists will find a way to rid a person of this dangerous disease completely. However, it can only reverse the disease if the unhealthy personality has not displaced the real one. With a severe schizophrenic defect, the person loses competence. There is a possibility of a fatal outcome.