We now understand that events such as these can actually change brain chemistry. This is why medication is can be helpful. Therapy can change brain chemistry, too and the combination of therapy and medication can be more effective than either by itself. Pi-polar disorder is a condition in which depression and mania alternate. See the American Academy of Family Physicians ' web site for a full and excellent description of this disorder, including symptomology and treatment.
Sunlight affects levels of seratonin in the brain.
In the winter when we spend more time indoors and there is less available sunlight, seratonin is affected in some people. These people become depressed only in the winter. Research has proven that for many people depression is best treated with a combination of therapy and antidepressant medication. However, if there is a reason that you are hesitant to take antidepressant medication, you can be helped by therapy alone. There are many different kinds of therapy available.