Medical science knows certain structures in the brain that are the areas most affected by depression. PET (Positron Emission Tomography) scanning of depressed and non-depressed people shows clear differences in the level of activity in certain brain centers and regions, like the hippocampus and limbic system, locus ceruleus, and the right frontal lobe of the cortex. Critical parts of these circuits depend on proteins called Serotonin and Norepinephrine. These "brain chemicals" are in short supply for those who are depressed. Insufficient Serotonin and/or Norepinephrine, whatever the reason for the insufficiency, is responsible for depression.

How is depression diagnosed?
Just like any other illness, depression is diagnosed by recognizing the symptoms and patterns, the history and severity of symptoms, and their persistence. Family history is important, since depression runs in families, and a person has a greater chance of having depression if it is found in their immediate family. The primary care physician is the most likely person to see someone's depression and diagnose it, though some depressions are masked as physical symptoms and aren't diagnosed until one sees a therapist, psychologist or psychiatrist.

Unfortunately, there are no lab tests to show depression, except experimental ones. There are psychological tests that can be helpful and need to be administered by a skilled psychologist. For the most part, depression is readily diagnosed by its clinical symptoms.

Facts About Depression
Major depression is the leading cause of disability in the U.S. and worldwide.

Depressive disorders affect an estimated 9.5 percent of adult Americans ages 18 and over in a given year, or about 18.8 million people in 1998. Nearly twice as many women (12 percent) as men (7 percent) are affected by a depressive disorder each year.

Depression can be devastating to family relationships, friendships and the ability to work or go to school. Many people still believe that the emotional symptoms caused by depression are "not real," and that a person should be able to shake off the symptoms. Because of these inaccurate beliefs, people with depression either may not recognize that they have a treatable disorder or may be discouraged from seeking or staying on treatment due to feelings of shame and stigma. Too often, untreated or inadequately treated depression is associated with suicide.

Does depression co-exist with other physical or mental disorders?
Depression cannot only co-exist with other physical or mental disorders, but it can be caused by and/or part of the syndrome of another disease. There are many physical and mental disorders that are associated with depression as a primary, secondary or just co-existing illness. Having more than one mental health condition is just as possible as having more than one physical condition, not to mention the potential for having both.

Research Findings
For information on national research please contact the following organizations:

Treatment
Antidepressant medications are widely used, effective treatments for depression. Existing antidepressants influence the functioning of certain chemicals in the brain called neurotransmitters. The newer medications, such as the selective serotonin reuptake inhibitors (SSRIs), tend to have fewer side effects than the older drugs, which include tricyclic antidepressants (TCAs) and monoamine oxidase inhibitors (MAOIs). Although both generations of medications are effective in relieving depression, some people will respond to one type of drug, but not another. Other types of antidepressants are now in development.

Certain types of psychotherapy, specifically cognitive-behavioral therapy (CBT) and interpersonal therapy (IPT), have been found helpful for depression. Research indicates that mild to moderate depression often can be treated successfully with either therapy alone; however, severe depression appears more likely to respond to a combination of psychotherapy and medication. More than 80 percent of people with depressive disorders improve when they receive appropriate treatment.

In situations where medication, psychotherapy and the combination of these interventions prove ineffective, or work too slowly to relieve severe symptoms such as psychosis (e.g., hallucinations, delusional thinking) or sociality, electroconvulsive therapy (ECT) may be considered. ECT is a highly effective treatment for severe depressive episodes. The possibility of long-lasting memory problems, although a concern in the past, has been significantly reduced with modern ECT techniques. However, the potential benefits and risks of ECT and of available alternative interventions should be carefully reviewed and discussed with individuals considering this treatment and, where appropriate, with family or friends.

Disease Information Sources: National Institutes of Mental Health and The Fort Hamilton Hospital Psychiatry Services