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Biology 202, Spring 2005
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Causes of Depression: Internal or External?


A Tomasulo

One of the most frustrating questions regarding the states of happiness and depression is whether internal or external factors are responsible for these psychological states. When we are depressed, is it because of the genetic build up of our brains? Or is it because of a negative environment? Based on the declaration of Emily Dickinson, "The Brain - is wider than the Sky/ -For - put them side by side /- The one the other will contain/ With ease - and You beside" insisting that brain = behavior and only internal factors can be responsible for depression. Can there be absolutes? Can we declare that either genetics or the environment is solely responsible for the psychological well being of a person? The lines between normalcy and clinical depression are constantly blurring and evolving. Further, depression has become one of the most significant mental conditions of our time. By the year 2020, it is predicted to be the second most debilitating condition, after heart disease (1). The increasing instances of depression, due to the changing standards for clinical depression, and the idea that brain = behavior have lead me to believe that there are no absolutes; that depression and happiness are caused by both internal and external factors. I will attempt to support this argument by examining evidence provided by The Science of Happiness: Unlocking the mysteries of mood by Stephen Braun, and the January 17 2005 edition of Time Magazine "The Science of Happiness".

Stephen Braun's research provides ample evidence to support Emily Dickinson. By studying antidepressants and their activities in the brain, he suggests that brain does equal behavior and that depression is caused by genetics instead of one's surroundings. Antidepressants, such as Prozac, are ultimately successful, although they can take up to a month to become effective (2). The reason for this time lapse in between administering these drugs and their effect is because these drugs stimulate the growth of dendrites in the brain, a process that can take several weeks. The growth of dendrites increases the flow of information between neurons, thus increasing the versatility of the brain and decreasing the chances of depression (2). Because neurons store information, they cannot be "renewed" because people would suffer from a constant memory loss (2). So "old" neurons continue to exist and "new" ones grow. The growth of these neurons allows the brain to send more information effectively, which in turn leads to more parts of the brain, including the pleasure centers, to be stimulated. Thus a person's behavior or mood can be altered by manipulating the way the brain functions. Braun also examines the work of Richard Davidson, neuroscientist of University of Wisconsin at Madison, who researched the importance of the front of the human brain: the prefrontal cortex. Based on his research the prefrontal cortex is largely responsible for our emotions "abstract reasoning, complex analysis, and foresight" (2). The prefrontal cortex is divided in two. The left half functions as a behavioral approach system. It forces the "outward" behavior of people (2). This is what encourages people to go forward in pursuit of happiness and survival. On the other hand, the right prefrontal cortex is the half that is responsible for inhibitory behavior. It is the right side that is in control of the "flight or fight" thought processes (2). This side of the prefrontal cortex that prevents us from running into oncoming traffic, or to react to stress. If the left side is more active, the person is viewed as happier, eager to learn and take advantage of opportunities. Whereas increased activity on the right side of the brain usually leads to a more introverted individual. According to Braun and Davidson, antidepressants are actually responsible for stimulating more electrical activity in the left prefrontal cortex as well as for the stimulation of neuron growth (2). Therefore, a person can have a more active left prefrontal cortex, making them less apt to be depressed, because of the genetic build up of his or her brain. According to this research of antidepressants and their effects, it is safe to assume that genetics are indeed responsible for depression. If the brain's activity can be manipulated by chemicals, and this manipulation results in the change of psychological state, then Emily Dickinson is right about the brain equaling behavior, and genetics are responsible for depression and happiness.

However, in a special edition of Time magazine from this past January 2005, an alternate argument was made. According to researcher David Lykken, people are actually in control of their psychological state "It's clear that we can change our own happiness levels widely up or down" (6). Psychologist Martin Seligman proposes that we are in control of reaching our ultimate happiness capacities by following these components: pleasure, engagement and meaning (7).. This means that we are in control of achieving happiness by pursuing personal pleasures, by engaging in relationships with those surrounding us, our activities and professions, and by applying our knowledge and skills to serve others (6). The Centers for Disease Control and Prevention support Seligman's ideas of pleasure, engagement and meaning leading to happiness. In a report titled "Marital Status and Health: United States, 1999-2002", it was proven that married couples are less likely to suffer from psychological disorders than are single people (5). Therefore individuals benefit psychologically from engaging in a relationship with another. A neuroscience professor from Stanford, Brian Knutson, researches our control over our happiness by using MRI. By studying the brain activity of people who were informed they would be winning money, he noticed activity in pleasure centers of the brain. The levels of activity depended on the amount of money won as a prize (4). His findings suggest that is the idea of feeling good that can induce brain activity and therefore happiness. If this is true, then situations in our environment can frequently induce happiness. For example, if we associate massages with feeling good, then the idea of receiving a massage will make the subject feel happy before actually having the massage. Clearly, Knutson's ideas were instigated by the work of Pavlov and his dogs (4). If we associate certain experiences and situations with being happy, and that in turn makes us happy, then we are indeed formed by our environments and experiences.

In conclusion, I believe that both internal and external factors affect psychological states. There are discrepancies in both arguments. For example, in researcher David Lykken's studies, although the majority of subjects supported the theory that genetics are responsible, 8% of the 4000 subjects reported that external factors (marriage, social status, money) effected their happiness. Despite being a small percentage, evidence that external factors are responsible exist. Further, there are those who take up to eight years to recover from the loss of a spouse (or the loss of a source of engagement) (6). On the other hand, there are those who do not become ultimately happier after winning the lottery (3). Somehow the end result of depression or happiness is achieved by a combination of environmental and genetic factors. Whether one can become depressed by the environment without inherent genetic factors has yet to be seen. More research must be done on depression and its causes not only for curiosity's sake, but for the sake of developing the "perfect" cure for depression. However the idea of the "perfect" antidepressant is another story and possibly another web paper.

Reference List:
1)Depression Learning Path , Major depression facts

2) Braun, Stephen. The Science of Happiness: Unlocking the mysteries of mood. John Wiley & Sons, Inc. New York. 2000.

3) Easterbrook, Gregg. "The Real Truth About Money." Time Magazine 17 January 2005.

4) Lemonick, Michael D. "The Biology of Joy." Time Magazine 17 January 2005.

5) Stein, Joel. "Is There a Hitch?" Time Magazine 17 January 2005.

6) Wallis, Claudia. "The New Science of Happiness." Time Magazine 17 January 2005

7)Reflective Happiness, About Happiness

Other Websites used for research:
http://www.thedoctorwillseeyounow.com/articles/behavior/depressn_5/

http://web.isp.cz/jcrane/IB/The_neurobiology_of_depression.pdf

http://www.nimh.nih.gov/publicat/depression.cfm#ptdep4

http://www.clinical-depression.co.uk/Depression_Information/facts.htm


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