Magnetic Resonance Imaging of the Human Brain
Clinical Depression, or Major Depressive Disorder, affects over 121 million people worldwide and is the second leading cause of disability (World Health Organization). Symptoms include a loss of interest in activities that used to bring pleasure, irritability, fatigue, feelings of worthlessness, inappropriate guilt, recurring thoughts of death, and drastic changes in sleep and eating habits. To be considered Depression, symptoms must occur mostly every day for a period of longer than two-weeks, and will have a negative impact on relationships, work, and social functioning.
Although these and other symptoms of Depression can be extreme or severe, it is possible to be suffering from Depression and not realize you are depressed. Some events, such as the end of a relationship or the death of a loved one, are clearly traumatic, and can lead to Depression, but Depression is not always caused by a single event, and can be caused by other factors such as chronic stress or childhood difficulties.
After analyzing years of research, physiologists, psychologists, medical doctors, and psychiatrists now generally believe that Depression is caused by biological and environmental factors combined with personal experience and psychological history (National Institute of Mental Health). To understand Depression, it is important to first understand the basic workings of the brain and the chemicals it uses to communicate with and regulate the body and its functions.
Whenever we think, feel, or do anything, chemical messengers called neurotransmitters are responsible for carrying the message from one brain cell to another. This chemical activity is reduced in the depressed person, resulting in a decreased ability to function mentally, emotionally, and even physically. These chemical messengers are carried by electricity and act quickly, but do not have long-lasting effect. The three neurotransmitters shown to be most involved in Depression are: serotonin, norepinephrine, and dopamine (All About Depression: http://www.allaboutdepression.com).
Hormones are released into the body through the endocrine system, a network of glands that works with the brain to control various functions of the body. The effects of hormones last a longer than the effects of neurotransmitters, but take longer to work. Changes in the brain chemistry of the depressed person are thought to affect the endocrine system through the hypothalamus, the brain structure that controls physical drives such as sleep, appetite, and sex drive, and abnormal levels of certain hormones have been found in those who are depressed even though these same people had healthy glands. The reverse can also be true, and those suffering from glandular illness such as hyperthyroidism can develop Depression.
By understanding the ‘how’ of Depression, we may better understand its symptoms and treatment options. Depression involves the body, mind, and heart (emotion), and produces a spiritual malaise. There are several types of Depression, and many different types of treatment. Some treatment options include antidepressant drugs, some involve cognitive or talk therapy, and some treatments use meditation and yoga. Still other options use a combination of these methods. It seems confusing and complex upon first glance, but Depression as an illness can be understood and managed one step at a time.
Comments
I read this from one of my favorite health blogs: A study published in the Proceedings of the National Academy of Sciences found people with a high family risk of developing depression had less matter on the right side of their brains. The finding was similar to that found in brains with Alzheimer’s disease according to the researchers.
blog.fitbrains.com
The most recent neurobiological research has located a specific genome (chromosome) that is strongly linked to major depressive disorder across generations, and that some scientists believe proves genetic predisposition. Amount of gray matter can be affected by many factors (including the natural process of aging), and it has recently been found that the brains of elderly people who have shrinking amounts of gray matter (we lose gray matter as we age) begin using white matter to take up the function of the decreasing gray matter. The decreased density of gray matter found in the prefrontal cortex of those depressed is also theorized to be created through childhood stress and trauma (Predisposition Locus for Major Depression at Chromosome 12q22-12q23.2; The American Journal of Human Genetics, Volume 73, Issue 6, Pages 1271-1281; V. Abkevich, N. Camp, C. Hensel, C. Neff, D. Russell, D. Hughes, A. Plenk, M. Lowry, R. Richards, C. Carter).
Great article. So important to understand the interplay between neurobiology and life experiences! As a cognitive behavioral therapist working with trauma victims it is often my experience that a combination of medication and therapy works best to alleviate chronic depressive symptoms.
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