A simple one-hour brain scan could predict who will respond to an antidepressant and who will not.

As this ScienCentral News video reports, it might help depressed people find the right drug that makes them feel better much sooner.

Brain Scans Predict Antidepressant Effectiveness

In any given year about one in six Americans suffer from clinical depression, according to Ian Cook, assistant professor of psychiatry at the University of California Los Angeles’ Neuropsychiatric Institute.

About 30 to 40 percent of depressed people who try a drug to relieve their symptoms will have to try another medication or a combination of medications before they find the antidepressant that works for them. It may take anywhere between “a couple of weeks and sometimes several months to see whether a person is going to respond to a particular medication,” says Cook. He warns that during that time the person may develop new symptoms, or their symptoms may intensify. They may even start to have suicidal thoughts or psychotic symptoms like hallucinations or paranoid delusions.

But now Cook is testing an imaging technique called quantitative electroencephalography, or QEEG, that can predict whether a person will respond to an antidepressant or not, within just 48 hours. The scan uses an algorithm to process the brain’s electrical signals. These electrical signals emanate from communication between brain cells. Electrodes attached to the patient’s scalp with a gel monitor the communication in the prefrontal cortex, the area of the brain that controls motivation and judgment. The signals are then converted into easy to read, color brain maps.

In a nine-week trial, Cook and colleagues tested 51 patients who had major depression or clinical depression. Their brain’s electrical activity was first recorded before they had any treatment. Then, half were treated with an antidepressant medicine, which was known to work, and the other half received a placebo.

“We then monitored them over the next weeks to see who would respond and who wouldn’t. And then we looked back to see what patterns of brain activity were present at the start and in the first week or two, that would be predictive of their clinical response”, says Cook. When Cook’s team compared their earlier brain scans to their clinical response, they found that a decrease in activity in the prefrontal cortex was a marker for those who would eventually respond clinically to the medication; people who did not show this decreased marker were those who would not respond clinically to the medication.

Cook says that this is an experimental study and other researchers need to replicate it to test its reliability. Similar findings would indicate that this scanning technique could be used to monitor depression treatment response and it might dramatically shorten the amount of time that it takes patients to get effective treatment, thereby helping people to get well much faster.

An unexpected finding of the study was that people who received the placebo and showed a clinical response, also showed a change in brain activity.

“But this time it was an increase in activity rather than a decrease, and it wasn’t seen early on," says Cook. "It was seen after two weeks or more of treatment. So indeed people who are taking placebo are showing changes in their brain activity as well, but they are very different from what we see in people who successfully respond to medications in treatment.”

Although he does not know why this happens, he and his colleagues have been “sufficiently intrigued” to start a new research project to study this further.

This study was published in the journal Neuropsychopharmacology and was supported by grants from the the National Institute of Mental Health and the National Alliance for Research in Schizophrenia and Depression. Additional support was received from Eli Lilly and Company and Wyeth-Ayerst Laboratories, makers of Prozac and Effexor, respectively.