Biological Markers of Response to Treatment in Major Depressive Disorder

• Quantitative Electroencephalogram measurements [ Time Frame: 8 weeks ] [ Designated as safety issue: No ]
  
• Serum BDNF Levels [ Time Frame: 8 weeks ] [ Designated as safety issue: No ]
  

Major depressive disorder (MDD) is a severe form of depression. MDD can significantly interfere with an individual's thoughts, behavior, mood, and physical health. People who suffer from MDD often experience feelings of worthlessness; they may feel hopeless and may be unable to cope with problems in their life. In addition, they often experience sleep disruption, loss of appetite, and chronic pain.

It often takes several weeks to find out if an antidepressant medication is going to work for someone. This research study aims to identify tests that are able to predict if a medication will work, even before a person starts to feel better. The first test is a measurement of the blood protein Brain-Derived Neurotrophic Factor (BDNF), which is involved with brain cell growth. The second test is a Quantitative Electroencephalogram (QEEG), which measures brain activity.

The study lasts for 8 weeks and involves 5 total visits to the clinic. Throughout the study, all subjects will receive either escitalopram (Lexapro) or citalopram (Celexa) on the basis of the study doctor's clinical judgment. The dose of the medications can be increased at any point in time if the study doctor thinks it is appropriate. After the first screen visit (which lasts about 3 hours), each subsequent half-hour visit will involve a 2-tablespoon blood draw to measure BDNF levels, as well as a QEEG in which small, painless electrodes are stuck to the subject's forehead and electrical activity of the brain is measured. At the end of the 8 weeks, subjects are offered 3 months of free follow-up care, including medications.