Chemical imbalance is said to be the root of depression, but what does that mean? Our organisms are so complex that numerous chemical reactions are happening all the time inside of us and it is difficult sometimes to pinpoint exactly what the cause of one person’s depression is. Therefore, two people who have the same or similar symptoms might have completely different causes for their depression. Unfortunately, a lot of things can cause a person to be depressed and these causes range from stressful life events, faulty mood regulation, all the way to genetics.
The many inner workings of our brains are still a mystery to scientists, but there has been huge progress in the past couple of decades. Using brain imaging such as PET, SPECT, or fMRI scans, scientists have been able to pinpoint which parts of the brain are responsible for our moods. Their research has shown that the amygdala, the thalamus, and the hippocampus are all connected to depression. For example, the hippocampus is usually smaller in people suffering from depression. This also relates to stress since stress can hold back the production of new cells in the hippocampus.
Genes determine the color of our eyes, how we look, how we behave, but they can also be the reason why we develop some health conditions throughout our life. That is why doctors usually ask you about your family history of illnesses before they start any treatment – if somebody in the family had a certain disease, there is a chance the offspring could have it as well. Since mood is not affected by a single gene but by numerous genes, it is difficult to determine exactly which one is the cause of depression in a person who has the genetic predisposition for it. Genetic research aims to figure out the exact function of each gene. Once scientists know which genes are at fault, they will be able to provide the patients with individualized medication for their exact type of depression, which will help the treatment immensely.
Stress is our defense mechanism and we need it to survive. When we are stressed, the hypothalamus releases the CRH hormone, which in turn, after some other processes activates the release of cortisol. This is when our blood pressure rises, the heart starts beating faster and breath quickens – our body is preparing us for the dangerous situation we are in. However, CRH is also connected to your thoughts, feelings, and emotions. Usually, stress lasts some short amount of time, and then our body returns to normal.
In cases of prolonged stress, CRH is present in the body more than it should be, which means that it is affecting our emotions more than needed, which can be a cause of depression.
When we experience early loss or trauma in youth, we might be more prone to stress, anxiety, and depression later in life. Some research even shows that early trauma alters the brain in some way, which could leave the person more vulnerable in the future. However, more research needs to be done to determine the exact connection between the two.