Question: Are there any tests (e.g., blood tests, genetic tests, brain scans) that can predict which antidepressant may be helpful?
Answer: Right now, the state of the art for selecting antidepressant medications is really one of trial and error. We choose the medication that we think is the most likely to help a patient. And then we stick with that for a period of six to twelve weeks to see if it's going to help the patient get better. We get the patients better with any one medication usually about half the time, and really only about a third of time are we going to be successful in getting somebody completely over their symptoms of depression with just the first medication that we try.
As a result there's a lot of interest in finding ways to predict whether a particular medication's going to be helpful for a specific patient. One way we're trying to do this now is with genetic testing. And there are a number of studies out there which suggest that genotyping a patient may be useful.
The problem is the results are very conflicting, and there really is no one genetic marker which seems to reliability predict whether a medication is going to be helpful for a particular patient. One line of research that we've been developing has been the use of quantitative electroencephalography or quantitative EEG. This is a technique where we place electrodes on a patient's scalp, and we record brain electrical activity right before and then shortly after we start a medication on a particular patient. We found that changes in brain electrical activity within the first few days of antidepressant treatment seem to be useful for predicting whether a medication is going to be helpful to a particular patient.