Are Mental Illnesses Hereditary?

Many times people tend to wonder if they will get a mental illness if someone in their family happens to be suffering from one. Scientists have been working for many years now to find the answer to whether mental illnesses are hereditary or not. They have been trying to single out the gene or genes that cause mental disorders such as autism, Alzheimer’s, ADHD, alcoholism, schizophrenia, depression, and many other such disorders that are known to have a major genetic component. Research has shown that many of the mental disorders are actually hereditary and can be passed on from one generation to another. Determining whether or not mental illness can be inherited is a hugely important factor for families affected by such disorders. Here we take a look at what the research says about mental disorders being hereditary.

Are Mental Illnesses Hereditary?

Are Mental Illness Hereditary?

A study done by the University of Wisconsin-Madison performed on young monkeys has shown that mental illnesses, such as anxiety might just be hereditary. Researchers scanned the brains of young monkeys when a stressful situation happened and then the results of the scans were compared to the scans of their relatives and parents. The scans showed that the more anxious the baby monkeys were, there were three different areas of their brains that lit up. It was also observed that these areas lit up in the same pattern as the parents of these baby monkeys. The experiment showed that these anxious areas of the brain that lit up appeared to have been inherited, as the parents also displayed the same pattern that lit up in their brains. This is just one of the studies that have shown that mental illnesses appear to have a strong genetic link.

Why Is It Important To Find Out Whether Mental Illnesses Are Inherited?

It is absolutely crucial to determine whether mental disorders are hereditary for many reasons. To begin with, understanding whether mental disorders have a genetic link helps people having these disorders make informed decisions about whether or not they want to start a family while having the risk of mental disorders being passed on to their kids. Being informed about this will also help parents better understand the behavior of their children from an early stage itself. For example, if your child exhibits anxious behavior, then you will be better aware that the child might develop a mental disorder, such as depression at a later stage in life.

Which Mental Disorders are Hereditary?

There are many mental disorders that are known to have a genetic link. However, not all the genes associated with mental disorders have been identified as of today. There are some mental illnesses that have been proven to be hereditary. Some of the mental disorders and their genetic links are discussed below.

  1. Depression

    A team of British researchers has recently successfully isolated a gene that is suspected to be the dominant gene in family members who have depression. The chromosome name 3p25-26 has been shown to occur in more than 800 families that suffer from recurrent depression. The researchers believe that about 40% of people who suffer from depression can trace the disorder to a genetic basis. The remaining 60% can be attributed to environmental and other factors such as grief, trauma or stress. Their research showed that people whose parents or siblings have depression are nearly three times more likely to also have depression.

  2. Obsessive Compulsive Disorder (OCD)

    Research on the genetic basis of OCD has been going on for a long time. In 2000, though, researchers were able to show a definitive result that proved that OCD has a genetic link. The study looked at OCD patients from Baltimore and Washington and was able to successfully determine that there is a strong connection between developing OCD yourself and having a family member or more who suffer from OCD. It was also shown that in such cases, OCD tends to develop at a young age itself. So it can be safely said that OCD is a mental disorder that is hereditary.

    Furthermore, in 2010, another study also revealed the potential chromosomes that are likely to be responsible for causing OCD. This study provided a lot of hope to families who have members who suffer from OCD; though there is still a long time to go before a cure based on genes can be established. There is also another train of research that indicates that OCD may also be caused by environmental factors. Therefore, more research is still required to prove whether or not heredity is solely responsible for causing OCD, or if genes are just a part of the disorder.

  3. Schizophrenia

    Schizophrenia has been known for being one of the toughest mental disorders to diagnose and treat. With new research, it is strongly believed that there is an underlying chemical imbalance that occurs in the brain that causes this mental disorder to develop. Scientists believe that it is this imbalance of chemicals that is inherited from relatives or parents. For example, a parent who suffers from schizophrenia is more than 40% likely to pass this mental disorder on to their child. Even in the case of identical twins, if one twin has schizophrenia, the chances of the other twin having the same condition go up by about 50%.

    A study done in 2014 aimed to show what the genetic basis might be for schizophrenia. Research showed that there was not one gene responsible for schizophrenia, but instead, there are many different genetic problems that are thought to be causing separate schizophrenic conditions. For example, a study showed that there were eight separate gene clusters that were linked to either different types of schizophrenia. Another study done on 113,000 participants, found that there are actually 128 different genetic variants that are related to schizophrenia. This study was revolutionary because most of these genetic variants had never before been linked to any brain problems before this.

    Yet another 2014 study done at Harvard found that in schizophrenic brains, the insulation and wiring of the nerve fibers were not functioning properly. The researchers of the study believed that this improper functioning of the nerve fibers was also an inherited condition.

  4. Bipolar Disorder

    Bipolar disorder is a mental condition that is also believed to be caused by a cluster of genes rather than one single gene. Similar to schizophrenia, a chemical imbalance is also suspected to be the cause of bipolar disorder, though several environmental factors are also known to contribute to bipolar disorder as well. However, the chances of bipolar being an inherited condition are high. Take the example of identical twins. If you have a twin who has bipolar disorder, then your chances of having the condition actually go up by nearly 90-95%.

Conclusion

There is no doubt that genetics are to blame for many mental illnesses; and mental illnesses are and can be hereditary. However, we are still many years away from developing a gene therapy that can help treat these mental disorders effectively. Nevertheless, a lot of research is still required for firmly establishing the genetic basis of mental illnesses.

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References

  1. Sullivan, P.F., Neale, M.C. and Kendler, K.S., 2000. Genetic epidemiology of major depression: review and meta-analysis. American Journal of Psychiatry, 157(10), pp.1552-1562.
  2. Lichtenstein, P., Yip, B.H., Björk, C., Pawitan, Y., Cannon, T.D., Sullivan, P.F. and Hultman, C.M., 2009. Common genetic determinants of schizophrenia and bipolar disorder in Swedish families: a population-based study. The Lancet, 373(9659), pp.234-239.
  3. Etain, B., Henry, C., Bellivier, F., Mathieu, F. and Leboyer, M., 2008. Beyond genetics: childhood affective trauma in bipolar disorder. Bipolar Disorders, 10(8), pp.867-876.
  4. Sullivan, P.F., Neale, M.C. and Kendler, K.S., 2000. Genetic epidemiology of major depression: review and meta-analysis. American Journal of Psychiatry, 157(10), pp.1552-1562.
  5. Grisham, J.R., Anderson, T.M. and Sachdev, P.S., 2008. Genetic and environmental influences on obsessive-compulsive disorder. European archives of psychiatry and clinical neuroscience, 258(2), pp.107-116.

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