New Genetic and Environmental Cause for Depression: Understanding 5-HTT

by on January 20th, 2011
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What You Need to Know About Causes for Depression
Scientists, psychologists, psychiatrists, and mental health professionals across the board have never found a single cause for depression which effects everyone suffering from depression in the same manner. Also, with every depression study published, it becomes extremely unlikely that there ever will be single cause for depression to blame. Furthermore, a cause for depression may be the starting point at which depression emerges, but it is the most current theory that the interaction between genes and environment is the cause for not only depression but a score of other mental illnesses, and that no cause can occur without both genes and environment effecting one another. However, scientists or journalists will often talk about a genetic cause with this understanding of gene and environment interaction, potentially misleading some into thinking only genetics are at fault. This article will explain how the new genetic cause for depression, the 5 HTT gene, is actually heavily influenced by the environment. Though, while the 5 HTT gene does help determine depression and is important to understand, it is not the only factor at play.

What is the 5-HTT Gene?
Those unfamiliar with scientific jargon do not need fear the title 5-HTT. However, to best understand the 5-HTT gene, we will first briefly discuss serotonin. Serotonin is merely something which everyone has in their brain (it is a neurotransmitter) which has been strongly linked with depression, along with a score of other disorders and conditions. Basically, the thought is that an imbalance of serotonin will create mood and potentially psychiatric issues in some people, and anti-depressants work to correct this imbalance. What determines our serotonin levels? New research has found that serotonin levels are controlled by the 5-HTT gene, or explained in scientific jargon, the 5-HTT gene is a “serotonin-regulating gene”. Therefore, scientists have asserted that different types of this serotonin-regulating gene will account for different amounts of serotonin and is partially responsible for depression. To clarify, the 5-HTT gene is a gene which controls serotonin (not depression) and then serotonin levels go on to influence or help cause depression in individuals. So, the 5-HTT gene helps cause depression, but it is not the most direct link to depression.

How Can the 5-HTT Gene Be a Genetic Cause for Depression If We All Have It?
Just as levels of serotonin may differ from person to person, there are two different kinds of 5-HTT. Some people may have the 5-HTT gene which works very well at producing and regulating serotonin. Individuals with this form of 5-HTT gene do not have to worry about a genetic cause for depression. Though, individuals with the other kind of 5-HTT gene, the kind which does not produce as much serotonin and is not as skilled at regulating serotonin, may have to worry about a genetic cause for depression. However, it is both incredibly important to understand that having the less productive form of the 5-HTT gene will not necessarily cause depression, and that those with the excellent form of the 5-HTT gene may still develop depression. This is where the gene and environment interaction comes into play.

How The Environment and Genes Effect One Another in Causing Depression
Remember that serotonin and the serotonin-regulating gene are not completely responsible for depression. In a depression study conducted by Avshalom Caspi, in which over a thousand children from New Zealand were studied from infancy to adulthood, Caspi made an important finding about the 5-HTT gene and it’s role in the cause for depression. Simply, Caspi found that those with the higher functioning 5-HTT gene have a greater capacity to deal with stress.

Potential Misconceptions About the 5-HTT Gene
Those with higher functioning 5-HTT are not impervious to depression given high amounts of stress. The new findings surrounding the 5-HTT gene and Caspi’s study on depression merely means that if two individuals, each with a different form of the 5-HTT gene, are subjected to the same stressful environment, those with the higher functioning serotonin-regulatory gene will tend to cope better. Moreover, this also does not mean that the individual with the gene calling for less serotonin will become depressed, it just means his 5-HTT gene is less prepared than that of his counter-part. Furthermore, any individual subjected to high amounts of stress may develop depression, regardless of their genetics or specific form of 5-HTT gene.

Therefore, though there is a genetic cause for depression, it is not really a cause; depression is the sum of how genetics interact with environment. Still, the new so-called cause for depression is incredibly significant, and as we learn more about the 5-HTT gene, we will increase the chance of developing better anti-depressants and eradicating depression more successfully.

Sapolsky, Robert M. “Monekyluv: and Other Essays on Our Lives as Animals”. New York; Scribner, 2005. Print.

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