Too often the general public relegates mental illnesses like depression, bipolar disorder, and schizophrenia to just that, mental illness, diseases of the mind. However, with modern science, we are beginning to see more and more the folly of this simplistic viewpoint. We are now seeing the science behind these illnesses; the changes in brain form, function, and chemical balance that alter how our brain functions and perceives the world around us. For the next month or so, in my “Exploring the Science of…” mini series, I will be talking about how what happens in our brain impacts what happens in our mind. For my first post, I would like to talk about how adjusting a few key elements in our brain can cause depression.
What Is Depression?
According to the National Institute of Mental Health (NIMH), signs of depression include long term feelings of sadness and emptiness, feelings of hopelessness, excessive tiredness, and more. Suicide is also a risk in those suffering from depression. Depression can be moderate to severe, and by NIMH’s count approximately 7% of the American population suffers from Major Depressive Disorder, a clinical term for depression. Depression is commonly treated with SSRIs (Selective Serotonin Reuptake Inhibitors) or MAOIs (Monoamine oxidase inhibitor), therapy is also helpful in changing thought patterns that can help make a person depressed.
A brain is a brain right? Wrong. Turns out there are a lot of things that can go awry inside our brain, just as there is in our body. One of the things that gets wonky in depression is something called neurogenesis, a fancy word for the generation of new nerve cells, particularly in the brain. It is believed that those suffering from depression cannot regenerate cells as fast as those without. This leads to loss of brain mass, particularly in the hippocampus, an area of the brain responsible for memory and recollection. Stress is believed to inhibit nerve growth, which may be one reason why the hippocampus is smaller in those that suffer from depression.
But the hippocampus isn’t the only area of the brain that changes due to depression. The amygdala, the part of the brain responsible for behavioral reactions and high level functioning, is also different in those that suffer from depression. According to Harvard Health, amygdala activity is much higher in those that have depression…even when they are not currently depressed!
Brain function isn’t just about form, what goes inside that form matters too, specifically the juice of our brain; neurotransmitters. Neurotransmitters are a bit like messengers, to keep it simple (it gets a bit complicated). They tell your brain what to do, how to feel, and how to function. The neurotransmitter most looked at in depression is called serotonin. Serotonin is responsible for feelings of happiness, so it’s no surprise that it might be involved in depression.
Those with depression do indeed have lower levels of serotonin in the brain. We all saw that coming, but how do we fix it? Adding more serotonin of course! Well, yes, and that is the goal of many anti-depressants on the market today, but perhaps not for the reasons you might think. In depression, not only does serotonin make you happy, it also regenerates nerve cells…see the connection? Serotonin levels rise, neurogenesis increases, the hippocampus is happy, and you’re happy. This also explains why anti-depressants take a few weeks to kick into effect; neurogenesis takes time.
Depression, like so many mental illnesses, is a complex disorder. It affects the brain as well as the mind, and requires treatment so that it’s sufferers can live a full, happy life. By understanding the science of why depression happens, scientists can create better treatment, tests, and therapies for it. If you feel you are suffering from depression, or have been diagnosed with depression, I hope you find comfort in knowing that this is a medical illness, with causes we can see, and not the fault of yourself. Thank you for reading and I hope enjoyed this, the first article in the “Exploring the Science of…” series.