Subtitles section Play video Print subtitles Hey there, welcome to Life Noggin. I may appear to be happy and animated all the time, pun intended. But some days I fall into a slump. We all do. It's a part of life. These feelings are real, and the effects aren't always just mental. You can actually feel them in a physical sense, too. But how? And why? Let's find out. Depression can be the result of a chemical imbalance in the noggin. Chemicals called neurotransmitters aid in sending messages to different nerve cells in your brain. Some neurotransmitters can control your mood. When you're depressed, these neurotransmitters might not be functioning properly, causing severe changes in mood. Depression can be caused by things like stressful life events, certain medications, death of a loved one, hormonal changes, and of course, caused by faulty mood regulation in the brain. One part of the brain affected by depressions is called the hippocampus. The hippocampus processes long term memory in recollection. It also registers fear, and it is actually smaller in people with depression. Ongoing exposure to stress impairs nerve cell growth in this part of the brain. Not only can depression have you feeling down, but it can actually physically affect parts of your body other than the brain. Chronic fatigue, insomnia, over-sleeping and general aches and pain are just a few examples. Pain threshold can be altered by abnormal functioning of the brain's neurotransmitters like serotonin, making people with depression more sensitive to pain. Another interesting physical change that can come with depression is eyesight. Recent studies show that the retinas of depressed patients were actually less sensitive to contrast. Contrast vision relies on cells that in turn rely on dopamine. People with depression are often shown to have less dopamine, which is important for drive and attention. These findings are still relatively new but very interesting. One unfortunate problem that comes with depression is the fact that it can actually increase your risk of physical illness. Stress hormones are increased which can lead to more problems. When we're stressed, our immune system's ability to fight off antigens of foreign bodies is reduced, making it more difficult to fight off infections. Corticosteroid, a stress hormone, can actually suppress the overall effectiveness of the immune system by lowering the amount of lymphocytes, which are cells that destroy the bodies of invaded viruses. Did you know the seasons can actually affect your mood? It's called seasonal affective disorder. When there's less daylight your, brain can increase neurotransmitters like melatonin. More daylight, and your brain will produce more serotonin. In the fall and the winter where there're shorter days and less daylight, your body might produce less serotonin and more melatonin. This imbalance can set up the brain for depression to some people who react to seasonal changes. Exposure to more light can help people maintain this chemical balance. If you or someone you know is depressed, please seek help immediately. You can check the links below for some online resources. Going to the doctor, seeing a therapist and thinking positively can work wonders So please don't be afraid to get out there and ask for help. What are some things in life that make you happy? Let's set up a positivity train in the comments. If you see someone with a similar interest in the comments, strike up a conversation! Or you can simply tell us what should we talk about next. And if want even more Life Noggin, check out this episode on "The Science of Happiness," and follow us on Facebook and Twitter. Links are below. I'm Blocko. This has been Life Noggin. Don't forget to keep on thinking.