Is It Possible To Inherit Mental Illness?
Is it possible to inherit mental illness? This is a question that you may have already asked yourself, especially if there is any case of mental disorder in your family. The point is that several researches show that certain disorders have a significant genetic load.
On the other hand, research has not yet managed to decipher all the questions about how this genetic load acts or influences. Science advances slowly. Little by little, we are learning more about the hereditary transmission of mental illnesses, although much remains to be discovered.
Today we understand disease, or better, health in general, as a product of the interaction between genetics and the environment. Furthermore, we know that in many cases what is inherited is not the disease, but the susceptibility to developing it.
What factors affect our health?
The onset of the disease will depend on many factors. This happens even in cases of dominant character heredity. Thus, you may spend your whole life without the disease manifesting itself if triggering factors do not occur (the spark that lights the fuse that carries the genetic charge).
So we talk about probabilities. Thus, there is no certainty that the child of a person with mental illness will manifest the same illness. On the other hand, it is possible to predict that the chances of suffering from this disease will be greater. And if the father and mother have the same disease, the chances increase even more.
Let’s look at how likely you are to inherit some of the more well-known mental illnesses.
Likelihood of inheriting mental illness: schizophrenia
Schizophrenia is a serious mental illness that affects certain brain functions, such as thinking, perception, emotions and behavior. Regarding their symptoms, they are classified as psychotic disorders, those in which patients lose touch with reality.
It is estimated that 1% of the population suffers from schizophrenia. It is also estimated, from several studies, that among the descendants of a schizophrenic father and mother, 40% will manifest the disease. Another 15% will have psychic anomalies, although it is not the same disease.
Among fraternal twins, the percentage of incidence remains unchanged. Among the one-eggs, the probability is 80%. It is considered to be a recessive type of inheritance, with incomplete penetration of the gene or genes carrying it.
Likelihood of inheriting a bipolar disorder
Bipolar disorder is a serious illness due to its associated danger and disability. It is also known as manic depression or manic depression. People with bipolar disorder are characterized by unusual changes in mood. Among mental illnesses, it is one of the most feared.
People with bipolar disorder sometimes feel very happy and “excited” and are much more energetic and active than usual. This is called a manic episode. Other times, people with bipolar disorder feel very sad and “depressed”, low on energy and much less active than usual. This is known as a depressive episode.
Bipolar disorder affects 0.4% of the population. The risk of having the disease increases when parents have it. Among the one-eggs, the probability is 95%. It appears to be a dominant-type inheritance, with incomplete gene penetration.
How likely is it to inherit oligophrenia?
The majority of profound oligophrenia (80%) are due to exogenous causes. That is, accidents or illnesses in intrauterine life or in early childhood. Therefore, they are not hereditary.
In mild or medium-intensity oligophrenia, 80% are linked to heredity. They are children of people with a low intelligence quotient. When the father and mother are oligophrenic, 80% of the children are mentally retarded. Only 40% have it when only the father or mother is oligophrenic.
A negative factor is that often oligophrenics bond with each other and therefore the probability related to genetics increases. This is because it is very difficult to find couples where the IQ gap is very large. The transmission mode is recessive type. Inheriting mental illnesses such as oligophrenia is possible, although most cases are due to exogenous causes.
What about other mental illnesses such as neurosis?
Neurosis is an abnormal reaction to experiences, the result of circumstances and, therefore, not linked to the genetic load. The overload of neurosis in the same family tree can be explained by “false heredity”. It is a reflex produced as a consequence of “emotional contagion” in a family context conducive to this.
There are hereditary antecedents in 70% of neurosis cases. The odds with identical twins are 83%. However, with fraternal twins they drop to 23%. Thus, the hypothesis of “emotional contagion” would be questionable.
Within the indisputable psychogenics of neurosis there seems to be a constitutional background. In other words, there seems to be a predisposition to react neurotically to pathogenic experiences. As we see, yes, it is possible to inherit mental illnesses. Some are more likely than others to be inherited. Twin studies and family histories have shown that mental health illnesses have a variable genetic contribution.
