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Does Depression Run in Families?

written by: Ivy N. McQuain MBA • edited by: Paul Arnold • updated: 5/27/2011

Genetics play a major role in many diseases and illnesses. From diabetes to high blood pressure there is a clear link between these illnesses and heredity. But is depression hereditary? This is a question that has many medical clinics scrambling to find an answer.

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    Genes and Disease

    Have you ever wondered how people in the same family can become affected by the same disease or illness? For instance, a grandmother has high blood pressure, her son has high blood pressure and his child has high blood pressure. The reason for this passing on of illnesses is due to genetics. Each chromosome contains many genes, the basic physical and functional units of heredity (Genetic Alliance, 2009).

    While there are no concrete studies answering the question, “Is depression hereditary?” there are some that reveal the possibility of a link between heredity and depression. Scientists believe that many mental disorders result from the complex interplay of multiple genes with diverse environmental factors (Centers for Disease Control and Prevention, 2011).

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    Family Case Study

    dna I have six uncles and six aunts and out of those 12 relatives at least seven have been diagnosed with some form of major depression. Now each of these relatives has children and at least one of their children, if not all, has been diagnosed with depression. Coincidence or hereditary? According to the Stanford College of Medicine, if someone has a parent or sibling with major depression, that person probably has a 2 or 3 times greater risk of developing depression compared with the average person (or around 20-30% instead of 10%).

    Depression is a mental illness that can greatly impact a person’s way of life through feelings of hopelessness, sadness and other negative thoughts which are contrary to the person’s natural ability to seek out and secure happiness. Many studies have proven that symptoms of depression may more than likely occur if someone experiences a tragic loss, has a history of abuse, drug related or physical, or other environmental issues. But as science continues to advance so does research to determine if depression can be passed down within a family. I for one, often look to my family and wonder how fathers/sons and mothers/daughters can suffer from the same mental affliction.

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    Genetic Studies

    There have been a number of studies that have looked for genes or genetic markers that might predispose someone to depression.

    In the summer of 2003, Duke Psychologist Avshalom Caspi reported that a gene called 5-HTTLPR played a significant role in depression risk. His research revealed that people with one or two copies of the short allele of the gene appeared to be more vulnerable to depression after a stressful event than people without the gene (Hamilton, 2009). This study was ranked one of the top discoveries of 2003; unfortunately, in 2009 the research was called into question by a study published in the Journal of the American Medical Association, that showed the initial findings had "not held up to scientific scrutiny" (University of Michigan Health System, 2011). The study went on to caution that any potential use of 5-HTTLPR as a screening tool for depression risk would be invalid (Hamilton, 2009).

    Fast-forward to 2011 and a team from the University of Michigan examined 54 clinical studies, dating from 2001 to 2010 with nearly 41,000 participants. The U-M analysis supports previous findings that individuals who had a short allele on a particular area of the serotonin gene (5-HTTLPR) had a harder time bouncing back from trauma than those with long alleles (University of Michigan, 2011). It found robust support for the link between sensitivity to stress and a short allele in those who had been mistreated as children and in people suffering with specific, severe medical conditions. But only a marginal relationship was found in those who had undergone stressful life events.

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    References

    Centers for Diseases Control and Prevention. (2011). Genomics and health: Mental health awareness. Retrieved fromhttp://www.cdc.gov/genomics/resources/diseases/mental.htm.

    Genetic Alliance. (2009). Understanding Genetics: A guide for professionals and patients. Washington, DC: District of Columbia Department of Health. Retrieved from http://www.pcdfoundation.org/education/understanding_genetics.pdf.

    Hamilton, A. (2009). Study: Depression gene doesn’t predict the blues. Times Magazine. Retrieved from http://www.time.com/time/health/article/0,8599,1905083,00.html

    Stanford College of Medicine. (2011). Major Depression and Genetics. Retrieved from http://depressiongenetics.stanford.edu/mddandgenes.html.

    University of Michigan Health System (2011). Resurrecting the so-called 'depression gene': new evidence that our genes play a role in our response to adversity. ScienceDaily. Retrieved from http://www.sciencedaily.com/releases/2011/01/110103161105.htm

    Photo Credit: Free Digital Photos. Photographer: jscreationzs.