This paper reflects the research and thoughts of a student at the time the paper was written for a course at Bryn Mawr College. Like other materials on Serendip, it is not intended to be "authoritative" but rather to help others further develop their own explorations. Web links were active as of the time the paper was posted but are not updated.
Biology 202, Spring 2005
First Web Papers
Less than a week ago, my family experienced the unexpected death of my grandmother. Although she was supposed to celebrate her eightieth birthday this week, we all still felt like she had left too soon. During the funeral procession, I watched the members of my family fall apart one by one. My mother, the youngest of the sisters but oldest of the brothers, was the most emotionally expressive out of the six siblings. But despite who appeared to be the most sensitive, I believe that each child felt the same blow and suffered from the same emotional repercussions resulting from their mother's death. Therefore, I do not question the impact of the matter, because I know it was hard for everyone, however, I wonder about the long-term effects this might have on some and not so much on others.
When tested with the same traumatic experience, there exists certain amount of acceptable sadness and grieving on everyone's part, but what sets apart the one person who will suffer the longest and continue to be under the spell of depression, while others accept and move on? When a justifiably horrendous experience strikes, who comes out of it stronger and who buckles under the pressure? Is it circumstantial, biological, or both? If we can argue that depression is a disease of the mind and the brain can exist without the mind, the same does not go for the reverse, then we might be able to assume that the brain and its neurological functions does, in fact, play a role in clinical depression.
The actual trigger of depression is not yet known; however, there seems to be evidence of the influence of genetics, environment, and neurobiological factors. In a neurochemical perspective, norepinephrine, dopamine, and thyroid hormones are several examples of hormones that are linked to the development of depression, but "research studies have implicated disturbances in the serotonin (5-HT) system and the Limbic Hypothalamic-Pituitary-Adrenal (LHPA) axis as two of the neurobiological alterations most consistently associated with mood-altering illness" (1). All of these hormones are part of a monoamine class, which has been found to cause depression when it is low in level or inhibited in the brain (2).
Although, it cannot be definitely argued that the brain is the main cause of depression, its disturbance in circuits and neurotransmitters make a significant difference in depression (2). The adrenal glucocorticoid, produced by the adrenal gland, not only regulates metabolism, but also interacts with serotonin 5-HT during severe stressful periods. The adrenal gland is linked to the region where serotonin is produced by limbic HPA axis, the area in which arousal, sleep, appetite, pleasure, mood is regulated (1). Because the malfunctioning of these behaviors are some of the symptoms of clinical depression, it is hard to ignore the role it might play during stressful times and the ways in which people respond. Of course it can be asked whether the people who suffer from depression are born with slightly different brains and neurobiology or if the stressful event causes the brain to suddenly function differently.
Another example of the importance of the brain and its function in handling stress is the hippocampus and its ability to control hormones and higher thinking in response to stress. Two receptors in the hippocampus work to control cortisol levels, when found in overabundance can cause depression (1). The prefrontal cortex is also related to higher thinking and executive function, and there is a discrepancy in these areas of the brains of depressed or suicidal patients (1). Now if this is true, then one might be able to assume that those who normally cannot display appropriate "higher thinking and executive function" throughout their lives might be more prone to depression.
Although we cannot say that stress actually causes depression, according to Lopez, stress very likely interacts with genetic disposition in the more vulnerable individuals, which can then lead to a mood disorder (1). But even with this hypothesis, the concept of stress seems so arbitrary. What might be considered a severe stressful situation in one life might be an everyday situation in another. Then, we can question the validity of the "genetic disposition of the more vulnerable individuals". Do the people who face dangerous situations everyday possess the exemplary genetic strength to live each day without resulting in some sort of emotional breakdown? Are these people just wired to deal better than those who live in a more comfortable environment? If not, then are those who lack the likely environmental influence to lead to depression not justified in their sufferings?
In addition, studies of identical and fraternal twins have shown that there is a higher and more consistent diagnosis of manic-depression for both individuals of identical twin siblings than those of fraternal twins (2). And since identical twins are genetically identical, while the fraternal twins are as genetically similar as any other sibling pairs, there is evidence that there also exists a genetic basis to depression.
These studies, like much of science, do not possess a definitive conclusion. There is an idea of what parts of the brain is linked to depression, but there is no definite cause. The continued studying in this area might ultimately bring about a cure or a means to avoid depression, yet there are certain biological factors that can never fully fathom much of the emotional and spiritual turmoil that the depressed patients must face. Edgar Cayce wrote,
"Yet, while the brain and the cords through which the nerves function are the channels, these are not the mental consciousness; though it is through the nerve plasm that the nervous systems carry impulses to the various forces of the system. There are the spiritual attributes, - desire, hope, will, - that function through the organs of reproduction, as well as becoming the import or motivative force in expression even in a material manner through the senses of the body ... In this instance we find that the glands of the body form the greater portion of such associations or activities" (3).
(1) http://www.thedoctorwillseeyounow.com/articles/behavior/depressn_5/; on thedoctorwillseeyounow website.
(2) http://www.lib.calpoly.edu/infocomp/modules/05_evaluate/WIC2b.html; on the Scientific American website.
(3) http://www.meridianinstitute.com/ceu/ceu14dep.html; on the meridian institute website.
| Course Home | Serendip Home |