Depression and anxiety have been discussed for years in terms of a chemical imbalance, leading many people to believe that increasing chemicals with medication is the way to correct the imbalance. Apparently, the best and brightest neuroscientists do not discuss the brain in terms of an imbalance anymore because it is not an accurate description of what is occurring.
Our brain is a chemical and electrical system that is in a constant state of fluctuation and adjustment. On a daily basis, the amount of rest we get, our diet, exercise or lack of, and our experiences affect our brain chemistry. The stress we live with and our genetics play a part as well.
What we think about and how we think about it also has an affect on our brain chemistry. Maintaining a positive outlook on life and seeing the best in most situations, generally leads to feeling better about our lives and ourselves. If we repeatedly review our failures and expect the future to be miserable and painful, we will most likely feel depressed and anxious.
When someone experiences trauma, the brain responds in ways that initially protect the person. However, in some cases the resulting brain changes make it hard to feel at ease, much less feel good. They may remain in a perpetual state of unrest that makes it difficult to function in their roles at home or work.
Stress that is beyond our ability to cope is can lead to changes in brain functioning that lead to periods of anxiety and depression.
As a result of severe trauma, the part of the brain that regulates emotion becomes overactive. The amygdala, which is responsible for rating experiences and in a sense grading there importance, is unable to return to its normal state, leaving the person in a state of perpetual anxiety. Neurochemicals in the brain are maintaining the anxiety.
A depressed person is generally over-focusing on the negatives with a brain that is negatively overrating normal human experiences. For example, someone who gets turned down by a potential employer sees that as terrible and an indication that awful things are bound to continue in the future. This type of awfulized thinking also maintains the neurochemistry required for depression and anxiety. The reality is that many people who are currently employed have been turned down before. This reality based thought is rational and generally optimistic, leading to a hopeful outlook and stable mood.
Not everyone who is genetically predisposed to depression will have a depressive episode. Likewise, not everyone who experiences a depressive episode was predisposed to it. Therefore, to say that some people have a chemical imbalance that causes depression is imprecise. It appears that all of us have brains that, when functioning normally, adjust our brain chemistry in a way that allows us to maintain emotional states that are appropriate to our experiences.
A brain that isn't functioning well may be supported with medication in order to do the footwork in therapy or marriage counseling. When normal mood is restored, new thought patterns and experiences can support mood stability and maintain it. The medication, in many cases can reduced gradually under a doctor's supervision and slowly discontinued.