Is Depression Hereditary
Depression is a common mental health problem that affects millions of people around the world. The disorder leads to a wide array of mental and physical health issues ranging from insomnia to exacerbation of chronic health conditions, and heart diseases due to sedentary lifestyles triggered by depression. Depressed individuals are also at a high risk of suffering from inflammatory conditions and associated autoimmune disorders such as arthritis and type 2 diabetes. The economic burden and medical complications linked to depression and its widespread prevalence have made it one of the leading medical conditions of interest to many researchers and professionals.
One of the most important question that researchers seek to understand about depression is its causes and risk factors. Studies have shown that depression is hereditary. A study of the human genome by a group of psychiatrists and scientists published in 2018 established that up to 44 genes are linked to depression. The meta-analysis of the whole human genome with the view of linking gene variants with depression found that the 44 loci in the brain associated with the mental condition were had unique anatomical features (“44 genes linked with depression”, 2018).
Further studies on the correlation between family as a predictor of suffering the mental health condition among women also established that women with a family history of depression where three times more likely to suffer from the condition in their midlife (Colvin et al, 2014). While stating that there is a strong link between depression and genetical makeup of an individual, Michael J. Meaney who is a neurologist who is also a specialist in psychiatry also pointed to the linkage between environment and depression. He asserted that depression is 50 percent hereditary and 50 percent environment-linked (Meaney, 2015).
Nancy Schimelpfening, who works at a sanctuary catering for individuals suffering from depression, notes that genes can increase and individual’s susceptibility to depression. The twin studies showed that identical twins had a frequency of 50 percent of both suffering from major depression due to the similarity of their genes. However, the frequency reduces to 20 percent for fraternal twins. She also notes that first-degree relatives are more likely to be diagnosed with depression because of the high levels of similarities in their genome. These relatives include children, siblings and parents. However, Nancy Schimelpfening points that the relationship between genetics and depression is complex and could involve numerous genes. She further notes that inheritance of these multiple genes associated with depression is a complex process that takes place in multiple ways (Schimelpfening, 2019 Jan. 16).
While these authors point to the linkage between genetics and depression, they also acknowledge that the mental condition can also be caused by other environmental factors. Specifically, Schimelpfening (2019) and Meaney (2015) note that depression can be caused by other factors other than genetics. Factors such as increased hormonal level especially during pregnancy and menopause among others may trigger depression. Moreover, malfunctioning of the brain neurotransmitters and trauma or chronic stress can also lead the mental condition (Schimelpfening, 2019).
Depression is a complex mental disorder with multiple causes. The various predisposing factors that make individuals susceptible to the condition interact in multiple ways that makes it implausible to point the exact cause of depression among two individuals. Even among individuals with similar genetical materials such as identical twins and first-degree relatives, the interaction between the genetics and environmental factors plays a big role in determining whether such individuals will suffer from the condition. Even in cases where genes have been identified as a leading cause, studies have shown that the genes are inherited in multiple ways that extend beyond understanding the specific loci involved (Colvin et al, 2014). Therefore, even identical twins old share a susceptibility frequency of 50 percent. In some cases, genes or the environment enhance the vulnerability of individuals to developing extreme mood swings, hopelessness, fatigue, irritability and other health complications associated with depression (Schimelpfening, 2019; Colvin et al, 2014).
In the study conducted by Colvin et al (2014) the experimental group had a prior history of depression. Therefore, genetics only increased their susceptibility to being depressed. Schimelpfening (2019) also noted this unique and complex interplay between family history or genetics and environment in determining the susceptibility of an individual to depression. She noted that while increased levels of hormones can lead to depression, the condition is more evident among individuals who are already susceptible either by other environmental factors or their genetics.
Depression is one of the commonest mental conditions globally with millions of people diagnosed with the condition or displaying its symptoms. However, the complexity surrounding depression and its causal factors makes it difficult to conclude that depression is exclusively hereditary. While acknowledging the direct link between genetical material and obesity, these studies and commentaries have also indicated that environmental factors also cause depression. Individuals who have already been predisposed to suffering from depression due the environment are more likely to experience severe symptoms of the condition if they have a family history and vice versa.
“44 genes linked with depression.” (2018). New Scientist, 238(3176), 19.
Colvin, A., Richardson, G., Cyranowski, J., Youk, A., & Bromberger, J. (2014). Does family history of depression predict major depression in midlife women? Study of Women’s Health Across the Nation Mental Health Study (SWAN MHS). Women’s Mental Health, 17(4), 269–278
Meaney Ph.D., M. (n.d.). Psychology Today: Health, Help, Happiness + Find a Therapist. Is Depression Hereditary? Psychology Today.
Schimelpfening N. (2019). How Genetics Can Factor Into Depression. verywellmind. Retrieved from: https://www.verywellmind.com/is-depression-genetic-1067317