May 26, 2013
Dr. Colleen Story
While similar, unipolar depression and bipolar disorder cause different struggles in individuals who have them. Unipolar depression is characterized only by bouts of depression symptoms, while people with bipolar disorder experience the same symptoms in combination with cycles of mania. There are many biological and psychological theories of the causes of unipolar depression, but bipolar disorder has for the most part been studied biologically. Finally, unipolar depression can be treated with medication, therapy, or a combination of both, but bipolar disorder cannot be successfully be treated with psychotherapy alone.
Unipolar depression has many possible underlying causes. First, stressful events often occur before an individual experiences unipolar depression. Biological factors include genetics, biochemical factors, brain anatomy, and brain circuits. Upon examination of the family tree of individuals who suffer from unipolar disorder, researchers found that up to 20% of their family struggled with it as well in comparison to 10% of the general population, showing a genetic relationship. Twin studies have shown a 46% incidence of unipolar depression in an identical twin whose sibling suffered from unipolar depression, and only a 20% incidence in fraternal twins, and several genes have been associated with the occurrence of the disorder. The first biochemical factor playing a part in unipolar depression is low activity of the neurotransmitter chemicals norepinephrine and serotonin. Overproduction of the hormone cortisol, normally produced during stressful situations, has also been linked to unipolar depression, along with some tentative theories about chemical deficiencies within neurons. The brain anatomy factors beginning to be seen as influencing unipolar depression are the dysfunction of brain circuits involving the prefrontal cortex, hippocampus, amygdala, and
References: Comer, R. J. (2011). Fundamentals of abnormal psychology (6th ed.). New York, NY: Worth. S, N. G., Rosenquist, K. J., Ko, J. Y., Baldassano, C. F., & al, e. (2004). Antidepressant treatment in bipolar versus unipolar depression. The American Journal of Psychiatry, 161(1), 163-5. Retrieved from http://search.proquest.com/docview/220478243?accountid =35812