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Apr 08, 2021
5 min read

Is depression genetic? Here’s what we know

Inheriting certain genes from your parents could make depression more likely. However, no one straight-out inherits depression, and genes are just one part of the puzzle. If you know that depression runs in your family, it’s helpful to be aware but not unduly worried.

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Reviewed by Felix Gussone, MD

Written by Robert Roy Britt

Disclaimer

If you have any medical questions or concerns, please talk to your healthcare provider. The articles on Health Guide are underpinned by peer-reviewed research and information drawn from medical societies and governmental agencies. However, they are not a substitute for professional medical advice, diagnosis, or treatment.

If one of your relatives suffers from depression, you might ask yourself if depression is genetic and if you’re at a higher risk for the disease, which can be distressing. As with other diseases, if depression runs in your family, you could be more likely to develop depressive symptoms (Sullivan, 2000).  However, that doesn’t mean you will develop symptoms of the depression. 

There are estimates on the importance of genes in the development of depression, but scientists just don’t know how much someone’s genetic makeup will eventually influence the onset of the condition, nor when or exactly why (or why not). That’s because multiple risk factors—not just genes— can predispose a person to depression, from brain biology to the individual’s environment and experiences in youth and throughout life (Kwong, 2019). 

Definitions of depression

Depression is an often-treatable psychiatric disorder affecting mood, behavior, and physical health. Major depressive disorder, as it’s also called, is “a serious medical illness that negatively affects how you feel, the way you think and how you act.” (American Psychiatric Association, 2013). 

Depression can lead to a range of emotional and even physical problems that can get in the way of normal functioning in all aspects of life. Increasingly, research reveals that depression is likely not a single, easy-to-identify affliction with a single cause (Institute of Medicine (US) Committee on Depression, 2009). Rather, there are many types of depression—including bipolar and unipolar, as well as seasonal or persistent—with a range of underlying causes, triggers, degrees of severity, and duration. 

Some 10% of U.S. adults suffered depression in a recent one-year period, and about 21% had been afflicted at some point during their life, according to a survey of 36,309 people done before the COVID-19 pandemic (Hasin, 2018). Other studies have put the rates closer to 5, and 15%, respectively, and that number can change depending on social and economic conditions. For example, rates of depression symptoms roughly tripled during the COVID-19 pandemic (Ettman, 2020). 

Depression can be diagnosed by a psychiatrist, who can then suggest treatments.

Symptoms of major depressive disorder

The clinical diagnosis for depression requires at least two weeks during which a person’s level of normal functioning declines due to at least some of the following symptoms (American Psychiatric Association, DSM-5, 2013):

  • Sadness or depressed mood most of the day
  • Loss of interest or pleasure in normal activities
  • Weight gain or loss
  • Poor sleep or oversleeping
  • Fatigue or loss of energy
  • Pacing, fidgeting, or other purposeless activity
  • Slowed movement or speech
  • Guilt or a sense of worthlessness
  • Difficulty thinking, concentrating, or making decisions
  • Recurring thoughts of death or suicide

Key differences that separate mere sadness or grief from a diagnosis of major depressive disorder include the sense of worthlessness or self-loathing and an inability to cope.

The role of genetics in depression

Heredity—a person’s genetic makeup, determined by a mix of genes inherited from both of their parents—can be a major contributor to a person’s tendency to develop depression. 

Twin studies suggest heredity is about 40 to 50% responsible for depression, and family studies have found depression in a first-degree relative (parent, sibling or offspring) could indicate a person is two to three times as likely to develop major depressive disorder (Lohoff, 2010). In addition, the most severe forms of depression tend to be fueled to a greater degree by genetics than by other factors (Sullivan, 2000).

But depression is complex, and it most often arises as the result of both genetic and environmental influences. Depression can be triggered or influenced by violence, abuse, neglect, poverty, or a range of other factors (UpToDate, 2021). These may include: 

  • Traumatic events or highly stressful periods in life
  • Several diseases and other medical conditions 
  • Differing brain structures or chemical imbalances
  • Pregnancy or childbirth
  • Drugs or alcohol

Genes that have been identified as contributing to depression each play relatively modest roles, however, and there is no firm evidence for a “depression gene” that causes depressive symptoms in everyone who might carry it (Shadrina, 2018).

Depression is also often depicted as being twice as common in women as men, based on several studies over the years (Albert, 2015). But it’s not clear why the apparent gap exists, nor whether the size of the gap is accurately depicted—or even if it exists at all. 

The possible explanations for the apparent gap illustrate how depression can be fueled by biology and experiences, regardless of any genetic factors: A comprehensive review of the research finds the gender difference, as measured in diagnoses, begins in adolescence and is especially acute for girls who enter puberty early. This gender gap widens during teen years. That suggests the stress that comes with puberty could play a role—not just the hormonal and physical changes, but the sexual harassment girls might experience as they develop. 

On top of all that, stereotypes may fuel a bias with two harmful consequences, whereby girls and women might be too readily diagnosed with depression, while it could be overlooked or discounted in boys and men. (Salk, 2017).

The role of genetics in treatments and therapies

Before treating someone with depression, psychiatrists aim to determine the severity of the disease, its likely causes, and which among several types of depression a person suffers from. There’s bipolar disorder, which has a depressive phase, accompanied by a flip-side manic phase. Other types of depression are called unipolar and lack the corresponding mania. 

Unipolar depression can be relatively short term, triggered by an event or a temporary condition, but two weeks is considered a minimum for diagnosis. Persistent depressive disorder, also called dysthymia, sets in for the long haul. Specifically, it’s defined as lasting at least two years. Seasonal depressive order (SAD) is typically related to the onset of winter and can be recurring (UpToDate, 2021). 

Knowing if genetics plays an important role in a person’s depression could help a psychiatrist prescribe the most effective preventions and treatments (Dunn, 2015). Treatments include talk therapy for milder cases, medication to modify brain chemistry, and cognitive behavioral therapy, which provokes a recognition of negative thoughts and behaviors then aims to change them.

To summarize: If depression runs in your family, it’s helpful to be aware but not unduly worried. No one straight-out inherits depression. While heredity can predispose a person, making depression more likely, there are many other factors at play and ways to overcome the condition. If you feel symptoms of depression coming on or notice them in a loved one, it’s vital to seek help from a healthcare provider.

References

  1. American Psychiatric Association. What Is Depression?Retrieved from https://www.psychiatry.org/patients-families/depression/what-is-depression
  2. Catherine K. Ettman, Salma M. Abdalla, Gregory H. Cohen, Laura Sampson, Patrick M. Vivier, Sandro Galea. Prevalence of Depression Symptoms in US Adults Before and During the COVID-19 Pandemic. AMA Netw Open. 2020 Sep; 3(9): e2019686. Retrieved from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7489837/
  3. Erin C. Dunn, ScD, MPH,1,2,3 Ruth C. Brown, PhD,4 Yael Dai, BA,1 Jonathan Rosand, MD, MSc,1,5,6 Nicole R. Nugent, PhD,7 Ananda B. Amstadter, PhD,4 and Jordan W. Smoller, MD, ScD1,2,3,8. Harv Rev Psychiatry. 2015 Jan-Feb; 23(1): 1–18. doi: 10.1097/HRP.0000000000000054. Retrieved via https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4309382
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  5. Jeffrey M Lyness (2021). Unipolar depression in adults: Assessment and diagnosis. Retrieved 04/2021 from https://www.uptodate.com/contents/unipolar-depression-in-adults-assessment-and-diagnosis
  6. Kwong ASF, López-López JA, Hammerton G, et al. Genetic and Environmental Risk Factors Associated With Trajectories of Depression Symptoms From Adolescence to Young Adulthood. JAMA Network Open. 2019;2(6):e196587. doi:10.1001/jamanetworkopen.2019.6587 Retrieved from https://jamanetwork.com/journals/jamanetworkopen/fullarticle/2736940
  7. Lohoff F. W. (2010). Overview of the genetics of major depressive disorder. Current psychiatry reports, 12(6), 539–546. Retrieved from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3077049/
  8. National Research Council (US) and Institute of Medicine (US) Committee on Depression, Parenting Practices, and the Healthy Development of Children; England MJ, Sim LJ, editors. Depression in Parents, Parenting, and Children: Opportunities to Improve Identification, Treatment, and Prevention. Washington (DC): National Academies Press (US); 2009. 3, The Etiology of Depression. Retrieved from https://www.ncbi.nlm.nih.gov/books/NBK215119/
  9. Paul R. Albert. Why is depression more prevalent in women? J Psychiatry Neurosci. 2015 Jul; 40(4): 219–221. doi: 10.1503/jpn.150205. Retrieved from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4478054/#!po=62.5000
  10. Rachel H. Salk, Janet S. Hyde, and Lyn Y. Abramson. Gender Differences in Depression in Representative National Samples: Meta-Analyses of Diagnoses and Symptoms. Psychol Bull. 2017 Aug; 143(8): 783–822. Retrieved from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5532074/
  11. Shadrina M, Bondarenko EA and Slominsky PA (2018) Genetics Factors in Major Depression Disease. Front. Psychiatry 9:334. doi: 10.3389/fpsyt.2018.00334. Retrieved from https://www.frontiersin.org/articles/10.3389/fpsyt.2018.00334/full
  12. Sullivan PF, Neale MC, Kendler KS. Genetic epidemiology of major depression: review and meta-analysis. Am J Psychiatry (2000) 157:1552–62. doi: 10.1176/appi.ajp.157.10.1552. Retrieved from https://ajp.psychiatryonline.org/doi/full/10.1176/appi.ajp.157.10.1552