"Unfortunately, we have a very poor ability to predict which antidepressant might be more effective for any individual," said Dr. Gregory Simon, a psychiatrist and mental health researcher with Group Health Cooperative in Seattle. "There's a long history of research using patterns of symptoms or biological measures -- chemicals measured in blood or spinal fluid -- to predict response to a particular antidepressant. None of those hoped-for predictors have significant value."
Genetic tests may provide some clues, he said, and the new study suggests there might be another approach. "It would not eliminate trial-and-error, but it would reduce the waiting time with each trial. But it's a long way from a study like this one to a test that's useful to patients and doctors."
Rasenick is hopeful, however, and he said the proposed test could do more than gauge whether drugs are working. It could conceivably measure the effectiveness of talking to a therapist, study co-author Rasenick said, since psychiatrists think psychotherapy has a physical effect on the brain.
Rasenick said more research and money are needed. The study was funded by the U.S. Public Health Service and the American Foundation for Suicide Prevention.
"The next step is to partner with people who are doing large-scale studies on individuals with depression and begin to look at this," he said. "We can begin to get hundreds of people and see if we can confirm that we're right."
More information
Learn more about depression from the National Institute of Mental Health.
