Can mental illness be inherited? This question is almost a concern for every patient.
This is closely related to the nature of mental illness.
Mental illness often occurs at a relatively young age. Taking depression as an example, the average age of onset is between 20 and 30 years old. Bipolar disorder tends to occur even earlier, often before adolescence. These individuals are often at or near the age of marriage and childbirth.
At the same time, the treatment of mental illness is a long-term process. The “long battle” undoubtedly brings greater and longer-lasting pain and burden to individuals and families, so the desire for the disease to improve and to avoid loved ones from falling into the same pain is stronger.
Patients often ask about the hereditary nature of their illness, worrying that if they start a family, they will pass the illness on to their children. Next, taking emotional disorders as an example, let’s briefly explain the hereditary nature of mental illness.
Firstly, conventional inheritance refers to the phenomenon where genes expressing corresponding traits of the parents are passed on to the offspring through sexual/asexual reproduction, allowing the offspring to obtain genetic information from the parents.
This genetic information is carried on the chromosomes. During processes like mitosis, the parental chromosomes carrying genetic information are passed down to the offspring according to certain rules, resulting in the offspring acquiring similar or identical features to the parents.
Of course, the process of inheritance also involves various changes in genes such as mutations, processes, modifications, and epigenetic modifications (methylation, acetylation), which can alter genetic information, ultimately leading to offspring developing features different from the parents.
However, in general, the vast majority of genetic information is stably passed on to the offspring, following Mendelian inheritance laws. Some characteristics following Mendelian inheritance laws can be calculated.
For example
If the chromosomes A and a of a flower represent the traits of red and white flowers respectively, as long as there is an A, it will exhibit the traits of a red flower. When the hybrids Aa (red flower) and Aa (red flower) cross, the probability of aa (white flower) is 25%. This is the precise probability people want to know.
Similarly, in humans, characteristics such as yellow skin, black hair, and black eyes of Chinese people are also hereditary. Once a cross-skin color marriage occurs, the skin of a mixed-race baby will not be purely yellow anymore.
However, in reality, not all genetic characteristics follow Mendelian inheritance laws. There are many characteristics with incomplete dominance and incomplete penetrance that cannot be calculated following these laws.
Mental disorders are a type of disease that does not follow Mendelian inheritance laws. However, the higher the degree of heritability, the higher the probability of developing a certain mental illness. Besides genetic factors, the occurrence of the disease is also influenced by various social, environmental, and psychological factors.
The hereditary issue of mental disorders has been detailed by numerous researchers through pedigree studies, twin studies, foster child studies, etc. For example, the heritability of depression is approximately 31%-42%, and for bipolar disorder, it is around 80%. Some diseases thought not to be hereditary actually have genetic characteristics, such as alcohol dependence, with a heritability rate of approximately 51%-65% in males, 48%-73% in females, even higher than depression.
What does heritability mean?
Heritability refers to the degree to which genetic factors play a role in the occurrence of a disease. For instance, if the heritability of depression explains that genetic factors account for 31%-42% of the disease, then the remaining percentage is due to the effects of environmental, social, and psychological factors.
This is why people often perceive that depression patients are more likely to develop the illness under stress and pressure. This also explains why in the treatment of depression, psychological therapy plays an irreplaceable role. From another perspective, it indicates that depression still has genetic characteristics. Although the probability is not high, individuals with high genetic predisposition need to pay more attention to psychological and environmental factors.
As opposed to depression, bipolar disorder has a heritability factor of 80%, which is almost equivalent to the probability of schizophrenia. This indicates that for such diseases, we need to pay more attention to genetic traits and emphasize the role of biological treatments, including medication and physical therapy.
Of course, in research, these diseases have been found to have an impact on the probability of occurrence through heredity. For instance, concerning depression, the first-degree relatives of the proband (the first person in a family to be diagnosed) have a 2-3 times higher likelihood of developing depression compared to the general population. For Bipolar I disorder (typical manic-depressive illness), the first-degree relatives of the proband have 8-18 times the likelihood of developing Bipolar I disorder compared to the general population.
In summary, although calculations cannot be made following Mendelian inheritance laws, through the aforementioned heritability and levels of risk, it is evident that the higher the heritability, the greater the likelihood of developing a particular mental illness.
Are mental disorders hereditary?
The answer is affirmative.
They are definitively influenced by genetic factors, but the extent of influence varies widely for different diseases and cannot be generalized.
Diseases like depression, with such levels of hereditary risk, do not necessarily affect marriage and childbirth. Love is everyone’s freedom, and marriage and childbirth are everyone’s rights, which should be respected for all individuals.
However, the purpose of marriage is happiness, and while in a diseased state, one not only cannot feel happiness but can also negatively impact previously harmonious relationships. Therefore, discussing marriage and starting a family during the acute phase of an illness is not advisable. Once the condition is under control through treatment, a good romantic and marital relationship can aid in the patient’s recovery and stability.
None of us know our probability of falling ill, and no one can guarantee not facing setbacks and hardships. Illness is not a choice, and suffering from it is itself a form of pain. It is essential to support, accept, and understand patients even more.
Welcome your submission, click “Read Original” for details
Contributor: Ningbo Health and Health Commission, Ningbo University Affiliated Kangning Hospital Li Guangxue
Editor: Provincial Health Protection Center Wang Qian
Layout: Liu Jiaqi
Previous Reviews
â–² Can you get heatstroke even by attending a concert at night? Keep this heatstroke prevention guide~
â–² Summer holidays are here, how should parents arrange the diet of “naughty children”?
â–² Near Lesser Heat, both Yin and Yang are deficient, health requires focus on benefits of Qi and nourishing Yin
Remember to “like + share”~
