DEPRESSION & ANXIETY DISORDERS

by Dennis Charney, M.D., Nat’l Institute of Mental Health

Dr. Charney focused on the devastating toll of mood disorders, exciting advances in treatment and what the future may hold.  He began with some staggering statistics to illustrate the magnitude of the problem in the U.S.

• Ten percent of Americans suffer from major depression in any given year.
• 2.3 million people suffer from bipolar disorder.
• Two out of three Americans who have mood disorders do not get proper treatment.
• Even when the diagnosis is made, treatment is frequently not obtained.

“There have been several recent studies that indicate that mood disorders are among the most serious of all medical diseases, not only psychiatric diseases,” Dr. Charney noted.

It also makes other health problems worse because it effects the entire body.  “Some forms of depression are associated with high level of stress hormones, as if the body is under stress all the time,” Dr. Charney explained.  In some patients the sympathetic nervous system stays hyperactive as if the body is under constant stress.  In addition, depression can affect the prognosis of certain illnesses, such as heart attack, Parkinson’s disease, etc.  Anecdotal evidence also suggests that the prognosis for certain forms of cancer may be altered if one is depressed.

Major depression and bipolar disorder appear to have many different causes.  Researchers believe environmental factors interact with one’s genes to increase risk.  Factors hat may increase vulnerability for depression include:

• Loss of social systems.
• Loss of a parent before age ten.
• Childhood history of physical or sexual abuse.

Sophisticated imaging studies show structural abnormalities in the brains of depressed patients.  An important finding replicated by a number of research groups is a reduction in the size of the hippocampus in patients with major depression.

One of the areas of focus in the chemical study of the brain has been the serotonin system.  Most drugs used to treat depression affect this brain chemical.  There are a number of different parts of the serotonin system that researchers can now see using PET imaging.  The hope is that their discoveries will eventually lead to better ways of diagnosing the disease to better tailor individual treatment.

In the quest for new medications, one area of focus is CRH, which is a neuropeptide.  There may be abnormalities in this peptide in the brains of patients with anxiety and depression.  Research indicates that in some depressed patients there are increases in function of CRH, and pharmaceutical companies are trying to develop a medication that will block the function of this neuropeptide.

Other future areas of research concern possible abnormalities in a brain system called the glutamate system, glutamate being an excitatory amino acid, high levels of the stress hormone, cortison, and neurogenesis – a process where new cells can be made in the brain.

Excerpted from NARSAD Research Newsletter,Volume 14, Sprint 2002

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