The Key Factor Which Causes Depression: Genetic or Environment
Introduction
Depression is a quite widespread disease of nowadays. Scientific sources and mass media already have some success in conveying to society the thought that depression is something more than a negative mood that can be changed by itself. It is the disease, and like any other disease, it requires treatment. Even though depression can be successfully cured, it is always a better way to prevent the disease.
However, preventing depression requires at first answer the question about the causes of this disease. There are different views on this issue. Some researchers claim that the main purpose of depression is genetic. Others argue that the environment is more important in the context of depression. However, as it often happens, and as the studies confirmed, both sides have correct suggestions and both causes, genetic and environmental, are important for the development of depression.
The Genetic Factor
As it was already mentioned above, some researchers claim that the genetic factor is the main cause of depression. For example, Lohoff (2010) noticed in the study that genetic factors play important roles in the development of the major depressive disorder (MDD), “as indicated by family, twin, and adoption studies, and may reveal important information about disease mechanisms” (p. 539). As one can see, some studies confirm the importance of the genetic factor for the development of depression.
However, not only the studies about the family, twin, and adoption show such results. England & Sim, (2009) refer to the studies of Kendler et al., (2006) and Sullivan, Neale, and Kendler, (2000), claiming that “about one-third of the risk for major depression in adults derives from genetic differences between individuals.”
Moreover, the researchers even point to the specific genes that are related to the development of depression. Thus, England & Sim (2009) noticed that there are “several genetic polymorphisms have been linked to an increased risk of depression in response to stress. Foremost among these are genes of the serotonin system (5-HT).” The fact that there are specific genes that take part in causing depression to do the thesis about genetic as the key factor that causes depression especially strong. In any case, it must be clear that for depression, as for any other mental disease, a genetic factor has quite an important role. Thus, Hyman (2000) wrote that “family, twin, and adoption studies have shown that, for schizophrenia, autism, manic-depressive illness, major depression, attention deficit hyperactivity disorder, panic disorder and other mental illnesses, the transmission of risk is due to heredity” (456). In this way, there is a list of many mental disorders caused by genetic factors, and it is logical that depression can be among them. Besides, as it was mentioned above, the studies found specific genes that are related to the development of depression.
The Environmental Factor
However, there is one more view on this issue. As far as depression is mental health, it is related not only to the physical state of the human body, including all complex process and part of it but also with the human psyche. It is known the fact that human psyche and state of the body are related. Depending on human emotions, the body produces different types of hormones which can affect the state of the body in one or another way and causes a person’s mood. Taking this into account one can consider an environmental factor as that which causes depression, comparing it with effect on low temperature on a human body. It is a known fact that if a human is under the influence of low temperature long enough, he or she can get sick. However, it is also known that the low temperature by itself is not the reason for disease.
Impact of low-temperature affects the human body, in particular, reduces the immunity, and that is why risks to get sick increases after the cases of freezing. The environmental factors can have a similar relationship with the depression. Even though the negative environmental factors cannot be the main reason for depression they can have a generally negative effect on the mental state of the human, thus, they become the key factor that causes depression because without their impact it could not develop. Some studies confirm that environmental factors cause depression. For example, Saveanu & Nemeroff (2012) claim that the “onset of mood disorders such as depression is undoubtedly impacted by stressful life events that occur in childhood” (p. 59). The authors considered the study in which the researchers paid attention to the experience of approximately two thousands women of various socioeconomic levels, and came to a conclusion that “those with a history of childhood physical or sexual abuse had an increased risk of depression and anxiety” (p. 59). The study also showed that women with a history of childhood abuse “have a four-fold increased risk of developing depression” and “early life trauma has also been shown to impact the clinical course of depression” (p. 59). Generalizing the conclusion of the study, the researchers identified four main points about patients with depression who have a history of childhood trauma. The researchers wrote that such patients have “(a) lower rates of remission and recovery, (b) longer episodes of depression, (c) a more chronic disease course, and (d) earlier onset of depressive symptoms” (Saveanu & Nemeroff, 2012, p. 59). These results clearly show that the life experience and environmental factors are significant as causes of depression.
However, it is not only one study that shows the importance of environmental factors in the context of depression. Beattie (2005) also identifies interpersonal relationships among the others factors that cause depression. Considering the types of interpersonal relationships that can cause depression Beattie (2005) identifies the following types: “(a) within the family, such as between the parents and between parents and children; (b) the social environment where differences in ethnicity and social class come into play; and (c) interactions between genders across age groups for both females and males.” These interpersonal relationships are quite clear as the causes of depression. The first two types are environments where a person is forced to be the most of the time. It is clear that issues in the family when it is not occasional difficulties but the permanent tensity, it will cause a permanent stressful state in which person can be vulnerable to mental disorders. The same is with another type of social environment in which a person forced to be almost every day. Interactions between genders, or, in some cases it can be within one gender, also can be significant for causing depression. Interpersonal relationships such as friendship or romantic relationships can be significant for personality; thus their breach or absence can have a negative impact on a person’s mental state, and that also can be the cause of depression.
Moreover, there is one more study that confirms the relation of environmental factors and depression. Peyrot et al. (2013) wrote that “stressful life-events, sexual abuse, and childhood trauma were significantly more frequent and educational attainment was significantly lower in major depressive disorder patients compared to healthy controls” (p. 94). It can be clear that there are some traumatic life-events, which can affect the mental state of a person during the whole life, especially if such events happened in childhood. In this way, the facts shown above proves that there is a strong relationship between environmental factors and depression and that environmental factors can be the factors that cause depression.
Combination of the Two Factors
As one can see from the facts shown above, both factors, genetic and environmental, are important for the development of depression. This is the correct answer on the question about the key factor which causes depression – both of them. One can notice that it is not only the compromise found between two opposite but the fact confirmed by the scientific studies. Thus, Saveanu & Nemeroff (2012) wrote that between genetic predisposition to depression and the impact of early traumatic experiences during critical phases of development there is a strong relationship. The researchers noticed that even though early life stress increases the risk of depression, “there are important differences in the way individuals respond to the same stressful event, and these differences may be explained in part by genetic factors” (Saveanu & Nemeroff, 2012, p. 60). In this way, the authors claim that both factors – genetic and environmental are important for the development of depression. Some researchers paid attention to the specific impact of the genes and noticed that “the short form of the gene triggers a more intense activation of the amygdala, also known as the cerebellar tonsil, a brain structure involved in emotions and recognition of danger signals” (CNRS (Délégation Paris Michel-Ange), 2011).
The researchers also noticed that “the activity of the amygdala varied according to not only to the form of the gene but also to the type of mental activity” (CNRS (Délégation Paris Michel-Ange), 2011). They came to a conclusion that “the stress experienced during the year also affected the influence of the gene on the activation of the amygdala – such “genetic-environmental” interaction being itself modified by the individual’s mental activity” (CNRS (Délégation Paris Michel-Ange), 2011). In this way, the importance of impact of both, genetic and environmental factors are confirmed by the facts shown above. England & Sim (2009) also come to this conclusion writing that those gene-environment correlations contribute to outcomes and appeals to the example when “genetic factors may influence a depressed person’s parenting styles as well as the offspring’s heritable traits so that the child’s genotype and rearing environment are correlated.” In this way, the authors show the importance of genetic factors. However, they also pay attention to their correlation with environmental factors, writing that “youth with particular heritable characteristics evoke reactions from others and select or create experiences that are congruent with their heritable characteristics—processes that might increase the likelihood of depressive outcomes under relevant conditions” (England & Sim, 2009). Carola et al. (2008) also pay attention to the correlation between the genetic factors and environmental factors. They used scientific approach and paid attention to the functions of gene, writing that “alterations in hippocampal gene expression and function underlie at least part of the interaction between 5-HTT and rearing environment and point to a role for this structure in the increased anxiety and depression-related behavior that is a risk factor for major depression” (Carola et al., 2008, p. 845). This result shows the correlation between the genetic factors and environmental factors in the context of the depression on the level of chemical processes in the human body. Considering the correlation between genetic and environmental factors one can see their close correlation.
Conclusion
On the one hand, the genetic factors cause some predisposition to depression. On the other hand, without some environmental factors, this predisposition can never develop. However, in some cases, the impact on the only one factor – genetic or environmental can be enough for the development of depression.
In this way, the above was considered the different views on the issue of the key factors which cause depression. There are different views on this issue. Some researchers claim that the key factor is genetic and show evidence to confirm this statement, including the studies which pay attention to the chemical processes in the human body. Other researchers claim the critical factor is environmental and confirms their statement with the studies which considered the different groups of people and came to the conclusion that people who felt an impact of negative environmental factors have a higher propensity for depression. However, as the one more type of the studies shown both elements have high importance for developing of depression; thus both factors can be critical.
References
Beattie, G. (2005). Social Causes of Depression. Great Ideas in Personality. Retrieved from http://www.personalityresearch.org/papers/beattie.html
Carola, V., Frazzetto, G., Pascucci, T., Audero, E., Puglisi-Allegra, S., Cabib, S., . . . Gross, C. (2008). Identifying Molecular Substrates in a Mouse Model of the Serotonin Transporter × Environment Risk Factor for Anxiety and Depression. Biological Psychiatry, 63(9), 840-846.
CNRS (Délégation Paris Michel-Ange). (2011). Depression: Combination of environmental, psychological and genetic factors. ScienceDaily. Retrieved from https://www.sciencedaily.com/releases/2011/11/111103143518.htm
England, M. J., & Sim, L. J. (2009). Depression in Parents, Parenting, and Children Opportunities to Improve Identification, Treatment, and Prevention. Retrieved 31 August, 2017 from https://www.ncbi.nlm.nih.gov/books/NBK215119/
Hyman, S. (2000). The genetics of mental illness: implications for practice. Bulletin Of The World Health Organization, 78(4), 455-463.
Lohoff, F. (2010). Overview of the Genetics of Major Depressive Disorder. Current Psychiatry Reports, 12(6), 539-546.
Peyrot, W. J., Middeldorp, C. M., Jansen, R., Smit, J. H., Geus, E. D., Hottenga, J., . . . Penninx, B. W. (2013). Strong effects of environmental factors on prevalence and course of major depressive disorder are not moderated by 5-HTTLPR polymorphisms in a large Dutch sample. Journal Of Affective Disorders, 146(1), 91-99.
Saveanu, R., & Nemeroff, C. (2012). Etiology of Depression: Genetic and Environmental Factors. Psychiatric Clinics Of North America, 35(1), 51-71.
