How mental illnesses are transmitted
The fact that mental illness can be inherited has been noticed for a long time. Today, geneticists confirm: indeed, mental disorders are more likely to appear in a child in a family where a relative suffered from a similar illness. And the reason for this are violations in the structure of genes.
There is such a thing as the coefficient of hereditary risk. The higher this coefficient, the higher the likelihood that the child will inherit the disease of relatives.
Only some mental illnesses are directly related to breakdowns in the genes, for example, Huntington’s chorea, the hereditary risk coefficient of which is 5000. For comparison, for such a mental illness as schizophrenia, it is 9.
How does the degree of relationship affect hereditary diseases?
The risk of developing a mental illness depends on the degree of relationship with a sick family member and on the number of sick relatives.
The highest probability of transmission of the disease in identical twins, followed by 1st degree relationship (parents, children, brothers, sisters). In 2nd degree relatives, the risk is significantly reduced
So, with schizophrenia, which is present in the mother and father, the probability of its occurrence in children is 46%, if one parent is sick – about 13%, if the grandfather or grandmother is sick – 5%.
What mental illnesses are most often inherited?
1. Disorders of the mental development of children
- Attention deficit hyperactivity disorder (ADHD) is manifested by impulsivity, difficulty concentrating, and increased physical activity. Often this disorder is combined with depression, behavioral disorders.
- Dyslexia – the inability to read, compare what is written with speech in some cases is hereditary.
- Autism is a severe mental disorder, expressed in violation of social adaptation. An autistic child is closed, he does not want to communicate with the outside world, he exists in his personal space. He does not tolerate any change, he has his own rituals, which he strictly observes. He constantly repeats stereotypical movements (rocking, bouncing) or the same phrases.
Autism is usually diagnosed in the first three years of a child’s life.
It is believed that the role of heredity in the occurrence of this disease is great.
2. Schizophrenia
This is a mental illness, which is characterized by disturbances in thinking, perception of the world, inappropriate behavior and an abnormal reaction to stimuli. The disease may be accompanied by agitation, delusions, and hallucinations. Patients are prone to depression and suicidal.
As a rule, the onset of the disease falls on the age of 20-22 to 30 years.
Heredity plays a significant role in the occurrence of this disease, but other factors are no less important: complications during gestation, difficult childbirth in the mother, infections, difficult psycho-emotional situations, and even birth in winter.
3. Affective bipolar disorder
Otherwise, this mental illness is called manic-depressive psychosis. It proceeds with an alternation of phases: depression and excitement, sometimes with aggression. There may be gaps between these phases.
4. Alzheimer’s disease
This disease develops after the age of 65 and is expressed first in forgetfulness, difficulty concentrating. Then there is confusion, loss of orientation in space. Irritability, unmotivated aggression appear, speech is disturbed. Dementia develops.
Rarely enough, the disease begins earlier, and here the hereditary factor, the pathological gene, plays a significant role.
Other mental illnesses that are inherited:
- Epilepsy.
- Psychopathy.
- Alcohol addiction.
- Dementia.
- Down syndrome.
- Chorea of Huntington.
- Syndrome “cat’s cry”.
- Klinefelter syndrome.
All of these mental illnesses can be inherited. At the same time, they can appear in a family where no one has suffered from such disorders. True, the risk of disease in this case is less, but it exists. So, you can get schizophrenia in a completely “healthy” family with a probability of 1%.
If there is a risk
Many people are afraid of passing on hereditary diseases to their children (even if distant relatives suffer from them), especially mental disorders, and therefore prefer not to have a child. Is such an approach correct?
A hereditary disease does not mean at all that a child will definitely have it. Yes, there is such a risk, but it is also present in children from “hereditary safe” families. Moreover, the chance of passing on a hereditary disease can be very low. It all depends on what kind of genetic disease exists in the family history, which of the relatives had a pathology, how severe the deviation was, and many other factors.
You can understand how big the risk is after passing a medical genetic examination. Therefore, in case of doubts and fears of “bad heredity”, the most correct approach would be to contact a geneticist.