by Carissa Weber
This post originally published on May 12, 2021. It has been updated with the most recent research for your benefit. Enjoy!
Every time a depression medication commercial comes on TV, I can’t help but think about the 264 million people worldwide that struggle with depression (which is close to 6% of the world’s population, or 1 in 15 adults to put it into scale) each day. That is a pretty big number! What breaks my heart even more, is the idea that this number could actually be higher because of how many people minimize the impact of their depression.
Depression comes in many forms, and it can impact everybody (although women are twice as likely to suffer from symptoms of depression than men are). Why is depression something so hard to talk about? So many of my clients have shared that it’s harder to talk about depression than anxiety because everyone just assumes “you’ll get over it” or “you’re just sad.” In this post, we will talk about how depression works in the brain, some of the scary statistics that happen when we don’t take care of our depression, and what to do if you fear you are one of those scary statistics.
What is Depression?
First off, let’s talk about the brain. If you recall from my first post, The Brain and Mental Health: The Breakdown (Literally and Figuratively), you may remember the breakdown of the limbic system and the role it has in mental health. Unlike anxiety, depression has many sources in our brain. Many people think depression is simply caused by a chemical imbalance. Well, that’s not true. According to Harvard health publishing (which is connected to the Harvard school of medicine), depression is defined as, “faulty mood regulation by the brain, genetic vulnerability, stressful life events, medications, and medical problems.” There are a lot of factors playing into depression! No wonder why it is easy to feel overwhelmed! The diagnostic Bible therapists use, the DSM-5, defines depression as this:
- Feeling sad or having a depressed mood
- Loss of interest or pleasure in activities once enjoyed
- Changes in appetite — weight loss or gain unrelated to dieting
- Trouble sleeping or sleeping too much
- Loss of energy or increased fatigue
- Increase in purposeless physical activity (e.g., inability to sit still, pacing, handwringing) or slowed movements or speech (these actions must be severe enough to be observable by others)
- Feeling worthless or guilty
- Difficulty thinking, concentrating or making decisions
- Thoughts of death or suicide
If you have a minimum of five of the above criteria for longer than a two week period, your therapist and/or Dr. would like to talk to you more about your depressive symptoms.
Depression and the Brain
Through imaging studies, scientists have been able to identify that darn amygdala and the rest of the limbic system (hippocampus, hypothalamus, and thalamus), all play a major role in depression. Despite feeling sluggish, unmotivated, and uninspired, that darn amygdala is working overtime (here I bet you thought I was going to say the amygdala wasn’t working at all!). You got it right, that darn amygdala is working overtime and sending messages all over the brain about why it is sad, overwhelmed, or saying those negative things about ourselves.
That darn amygdala is spending so much time turning every little sensory message into an emotional response, it hardly has time to let the prefrontal cortex in to say “do we really need to feel like this over all the peanut butter being gone?” Over time, the prefrontal cortex starts to loose its ability to assist in problem-solving, impulse control and identifying facts to support that darn amygdala’s emotional responses. Have you ever felt so unmotivated you couldn’t get out of bed? Some of that is because your prefrontal cortex has lost the ability to challenge what that darn amygdala and the thalamus are doing.
Interestingly enough, people who suffer from depression have a larger than average thalamus. Why is that? A study completed by the researchers at Southwestern Medical School showed that the thalamus is sending more and more emotional messages from the amygdala around the brain.
While the thalamus is pumping the brain full of emotional messages, it is also allowing the neurotransmitter, serotonin, to just hang out in the synaptic gap. What does this mean? This means serotonin, as well as dopamine and endorphins, are not dispersing around the brain, which is keeping you feeling sluggish, unmotivated, and just down. Scientists and researchers are still uncertain about what causes the brain to not move these feel good neurotransmitters around, but based on how anti-depressants work (which will be covered at a later time), getting serotonin and other feel-good neurotransmitters moving decreases the feelings of depression.
Genes and Depression
As we discussed in the post, Fight-Flight-Freeze: The Ultimate Coping skill and What Anxiety Really is: A Map to Distress, the hippocampus seems to slow down and shrink as that darn amygdala continues to say how stressed the brain is (you can thank that steady stream of adrenaline, noradrenaline, and cortisol for your shrinking hippocampus). One study showed the hippocampus shrank almost 16% in study participants with depression (MacQueen GM, Yucel K, Taylor VH, Macdonald K, Joffe RBiol, 2008). This same study also showed a smaller hippocampus is also a sign that depression could relapse (or come back) in the future.
One thing to keep in mind is the genetic factor with depression. Many people don’t realize we have a gene responsible for depression. Science has found 4 promising genes (12a, 12q23, 15q, and 18q) that seem to correspond with depression, serotonin receptors, and serotonin production (isn’t that fascinating?) (Lohoff, 2010). Couple this with a genetic predisposition to a smaller hippocampus, adrenal gland issues (also genetic), and you may be at risk for hereditary depression.
External Factors for Depression
Now that we have covered the biological reasons depression happens in the brain, we have to consider things outside of our body that contribute to depression. It is pretty common knowledge that chronic stress is a factor in developing depression. This stress can come from multiple areas: work, home, school, friends, family, substance use, chronic medical conditions, and even financial reasons.
Sunlight and Depression
As we covered in Seasonal Affective Disorder: A Reason for the Feeling, sunlight plays a huge role in depression. Natural sunlight helps our body produce vitamin D, a crucial vitamin needed for breaking down nutrients in our body, producing serotonin and dopamine, and helping our sleep cycles. If you live further away from the equator, you are more likely to struggle with Seasonal Affective Disorder, a subset of depression that happens when the seasons change. If you notice a change in your depression in the dark cold months (like many of us in Wisconsin), a sun lamp may help you out.
Diet and Depression
Did you know that diet could even be considered a factor in developing depression? Just like we discussed in Neurotransmitters: The Language of the Brain, serotonin develops out of tryptophan, which is an amino acid found in food we eat. If we are not getting enough food in our brain may not be able to move serotonin around like our brain needs. Are you busy binging on comfort carbs? Notice the last green thing you ate was a gummy worm? The lack of a BALANCED DIET could increase the chances of developing depression. Some of the foods you could eat to help increase the production of serotonin include (but not limited to) the following:
- Fish (especially salmon)
- Dairy products (milk, yogurt, cheese)
- Pumpkin Seeds
- Soy products
- Fish (especially salmon)
- Dairy products (milk, yogurt, cheese)
- Pumpkin Seeds
- Soy products
When you look at this list above, you may notice these foods are also high in protein, iron, and vitamin B. Not only do these carry the tryptophan for us, but they also help our limbic system improve our memory, focus, and connections between the prefrontal cortex and that darn amygdala. Now, rumor has it that carbs can help boost tryptophan and promote serotonin production. Carbs do this by releasing insulin into our body. the insulin helps reabsorb all the good things, leaving the tryptophan in your body for a longer period of time. Could this be why you crave pizza when you’re down in the dumps? Perhaps.
Hope on the Horizon
Speaking of external factors adding to our darn amygdala’s depression activating response, the last couple of years have been especially difficult for all of us. The uncertainty and economic impact of a global pandemic along with the looming shadow of social unrest and even war have left many of us overwhelmed to say the least. When you couple these factors with the unavailability of mental health resources, it can leave a person feeling hopeless.
I do have good news though for people that live in my home State of Wisconsin. Starting March 1st, 2022, I will be offering telehealth counseling services for private pay to Wisconsin residents. I am hopeful in the future to be able to take insurance. If you feel that you are in need of counseling, please check out my new website and business here.
Thank you so much for taking time to invest in your mental health and learning about the cycle of depression. I would like to challenge you to try behavioral activation. Even if it is just as an experiment, take time to evaluate your value system, identify things that (used to) bring you joy, and schedule a time to participate in something you know you are passionate about. Journal how it made you feel for a week or so. In the next post, we are going to go over some more coping skills known as cognitive behavioral therapy.
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- American Psychiatric Association. (2013). Diagnostic and statistical manual of mental disorders (5th ed.). https://doi.org/10.1176/appi.books.9780890425596
- Cowen, P. J., & Browning, M. (2015). What has serotonin to do with depression?. World psychiatry : official journal of the World Psychiatric Association (WPA), 14(2), 158–160. https://doi.org/10.1002/wps.20229. Retrieved from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4471964/
- Ferri, J., Eisendrath, S. J., Fryer, S. L., Gillung, E., Roach, B. J., & Mathalon, D. H. (2017). Blunted amygdala activity is associated with depression severity in treatment-resistant depression. Cognitive, affective & behavioral neuroscience, 17(6), 1221–1231. https://doi.org/10.3758/s13415-017-0544-6. Retrieved from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5728990/
- Harvard Health Publishing (2009, 2019). What Causes Depression? Retrieved from https://www.health.harvard.edu/mind-and-mood/what-causes-depression
- Lohoff F. W. (2010). Overview of the genetics of major depressive disorder. Current psychiatry reports, 12(6), 539–546. https://doi.org/10.1007/s11920-010-0150-6. Retrieved from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3077049/
- MacQueen GM, Yucel K, Taylor VH, Macdonald K, Joffe RBiol Psychiatry. (2008) Posterior hippocampal volumes are associated with remission rates in patients with major depressive disorder. Biol Psychiatry. 2008;64(10):880–883. Retrieved from https://pubmed.ncbi.nlm.nih.gov/18722590/
- Pandya, M., Altinay, M., Malone, D. A., Jr, & Anand, A. (2012). Where in the brain is depression?. Current psychiatry reports, 14(6), 634–642. https://doi.org/10.1007/s11920-012-0322-7. Retrieved from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3619732/#R26
- Tinsley, Grant and Gotter, Anna (2021). What Is Tryptophan? Retrieved from https://www.healthline.com/health/tryptophan
- University of Michigan (date unknown). Behavioral Activation. Retrieved from https://medicine.umich.edu/sites/default/files/content/downloads/Behavioral-Activation-for-Depression.pdf
- UT SOUTHWESTERN MEDICAL CENTER (2004). Severe Depression Associated with Greater Number of Nerve Cells in Thalamus Region of Brain. Retrieved from https://www.eurekalert.org/pub_releases/2004-07/uots-sda063004.php#:~:text=1%2DJul%2D2004-,Severe%20depression%20associated%20with%20greater%20number%20of,in%20thalamus%20region%20of%20brain&text=Southwestern%20Medical%20Center-,Individuals%20who%20suffer%20from%20severe%20depression%20have%20more%20nerve%20cells,Center%20at%20Dallas%20have%20found.
- World Health Organization (2020). Depression. Retrieved from https://www.who.int/news-room/fact-sheets/detail/depression