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By Dr. David Woo - October 20, 2020
Nature vs. Nurture is a scientific debate that asks the question, “Is human behavior determined by a person’s environment, or by genetic predisposition?” Environment (nurture) refers to the external influences someone experiences, such as their home environment and childhood experiences. Genetic predisposition (nature) refers to the genes that a person inherits from their parents.
Both environmental factors and genetics contribute to depression (a condition known to affect a person’s behavior, mood, and overall health), but is one more influential than the other? Let’s take a look at how each one can affect a person’s risk of developing depression.
Nature: How Genes Contribute to Depression
Depression is known to run in families–people who have a direct relative (a parent or a sibling) who has been diagnosed with depression are up to three times more likely to develop depression.(1)
Multiple studies conducted throughout the years reveal that inherited genes play an important role in the development of depression. However, there is no one gene that, when inherited, significantly increases the risk of depression. Several genes have a small influence on the development of depression.(2) Results from a genome-wide association study (GWAS) that analyzed the health records of over 1.2 million people tell us that there are 178 gene variants that can contribute to the genetic predisposition for depression.(3)
Nurture: How Our Environment Contributes to Depression
Researchers have established numerous environmental risk factors that contribute to depression, including:
- Upbringing: Children who grow up with a parent who is depressed are at an increased risk for depression. Behavioral changes in a depressed parent can negatively affect their children and increase the risk that they’ll develop depression or another mental illness later in life. (4)
- Trauma: Emotional, physical, and sexual abuse in childhood increases the risk of depression. (5)
- Negative lifestyle factors: Certain behaviors like overworking, abusing drugs and/or alcohol, and poor diet can contribute to depression.(6,7)
- Major life events: Stressful life events such as job loss, divorce, and loss of a loved one can trigger depressive episodes.(8)
Depression Develops When There is an Interaction Between a Person’s Genetics and Environment
A combination of risk factors that includes both one’s environment (nurture) and genes (nature) is necessary for someone to develop depression–one is not more important than the other. Although certain genes can increase someone’s risk of developing depression, inheriting one does not guarantee you will develop the condition. If you inherit a gene associated with depression and are exposed to certain situations or trauma in your life, you may be more susceptible to developing depression.
Additionally, a study published in 2016 suggests that a person’s environment can ‘override’ a genetic predisposition for depression. Researchers observed behavior in rats that were bred for depression. They found that providing a type of psychotherapy to rats that had an increased risk for depression alleviated their risk for depression.(9) This study suggests that depression may be able to be prevented in children with a high inheritable risk for depression using cognitive behavioral therapy.
Depression Treatment
If you believe you are at risk of developing depression, or if you notice signs of depression–like loss of interest in normal activities and/or hobbies, trouble concentrating, and feelings of worthlessness–, talk to your doctor. Your doctor will work with you to make a diagnosis and find the best treatment option for you.
Patients who do not find relief from depressive symptoms with antidepressants or who are hesitant about the side effects associated with antidepressants can ask their doctor about TMS (transcranial magnetic stimulation). TMS is a relatively new FDA-approved clinical depression treatment that uses magnetic stimulation to relieve depressive symptoms. Learn more about depression treatment in New York City.
Resources:
1. Weissman MM, Wickramaratne P, Nomura Y, Warner V, Pilowsky D, Verdeli H. Offspring of depressed parents: 20 years later. Am J Psychiatry. 2006;163(6):1001-1008. Link. Accessed September 28, 2020.
2. Lohoff FW. Overview of the genetics of major depressive disorder. Curr Psychiatry Rep. 2010;12(6):539-546. Link. Accessed September 28, 2020.
3. Levey DF, Stein MB, et al. Bi-ancestral depression GWAS in the Million Veteran Program and meta-analysis in >1.2 million individuals highlight new therapeutic directions. Nat Neurosci. 2021;24(7):954-963. Link. Accessed September 22, 2022.
4. Mattejat F, Remschmidt H. The children of mentally ill parents. Dtsch Arztebl Int. 2008;105(23):413-418. Link. Accessed September 28, 2020.
5. Negele A, Kaufhold J, Kallenbach L, Leuzinger-Bohleber M. Childhood Trauma and Its Relation to Chronic Depression in Adulthood. Depress Res Treat. 2015;2015:650804. Link. Accessed September 28, 2020.
6. Virtanen M, Ferrie JE, Singh-Manoux A, et al. Long working hours and symptoms of anxiety and depression: a 5-year follow-up of the Whitehall II study. Psychol Med. 2011;41(12):2485-2494. Link. Accessed September 28, 2020.
7. Rao TS, Asha MR, Ramesh BN, Rao KS. Understanding nutrition, depression and mental illnesses. Indian J Psychiatry. 2008;50(2):77-82. Link. Accessed September 28, 2020.
8. Stroud K. Stressful Life Events and Depression. Clinical Science Insights: The Family Institute at Northwestern University. 2010;2014. Link. Accessed September 28, 2020.
9. N S Mehta-Raghavan, S L Wert, C Morley, E N Graf, E E Redei. Nature and nurture: environmental influences on a genetic rat model of depression. Transl Psychiatry. 2016 Mar 29;6(3):e770. Link. Accessed September 28, 2020.
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