As a student of science and psychology, I am interested in learning about inherent biological mechanisms that are responsible for the various external experiences we go through on a daily basis. Why do people act the way they do, or why do humans feel a certain kind of way when watching a sad movie, or a funny movie or a scary movie?
Module 15.1, addresses the broad topic of Mood Disorders.
I wanted to know specifically about the chemical responsible for "depression". Why do we feel sad or down during not so happy times? What makes us feel that way? well, there are many factors that can help explain this mechanism, but in this post, I will talk mainly about the chemical imbalance in the brain.
Neurotransmitters, which are chemicals responsible for relaying most neural information from one neuron or nerve cell to the next have been helpful in explaining the case of depression.
The cause of depression, is dependent upon the volume or amount of these neurotransmitters being communicated throughout the neural pathways. If there is too much or too little then there is an imbalance or a breach to homeostatic event, which can then lead to the person feeling depressed or sad. The family of neurotransmitters that have been linked to depression are all classified in a group called monoamines which are further classified into three:
Serotonin, Dopamine, and Norepinephrine
Low levels of monoamines cause depression in humans. One study have found that high levels of an enzyme responsible for breaking down serotonin, the Monoamine Oxidase-A (MAO-A), is significantly higher in cases of depression.
Chemically, that is the explanation. Physiologically, the parts of the brain depression is most prevalent are:
The Amygdala, Thalamus, Hippocampus.
Depression, once again, is experienced by the human in effect of a biological mechanism... Some argue that this is not the only cause of depression, things like the environment, and genetics also influence the occurrence of depression. However, for me chemically and biologically explained is much more satisfying. If you want to learn about the physical effects of depression, I have included an image below:
Good luck and happy day!
Recently having studied the effects of serotonin and dopamine on the brain, this was perfect timing for me to have read your blog! Norepinephrine is actually an intermediate in the synthesis of dopamine and so they are of course interrelated. A deficiency in norepinephrine would lead to a deficiency in dopamine, which of course as you stated can result in depression. Serotonin is a BIG player in modulating mood and inhibiting that monoxidase enzyme, could also cause problem in sleep for individuals as well. Serotonin treatment would raise levels in the brain and alleviate the symptoms of depression. Awesome post!
ReplyDeleteDepression is one of the main factors that lead to suicide around the United States of America. Even though studies have proven that this disease that people partake can be fixed, it can come back if a person has a difficult event in their life. Lithium is one medication that people can take to help depression to decrease depression. I think in my opinion is normal to feel depressed in certain circumstances that happen in my life, but when it is out of my control I would go to therapy to see my options.
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