Can Brain Scans Pick Depression Treatment?

A small study suggests that a brain scan may give clues to people's likely response to depression treatment. The study included 62 people with major depression. All were given positron emission tomography (PET) scans to show activity in different areas of the brain. Then people were randomly assigned to treatments. Half received cognitive behavioral therapy, a type of talk therapy. The others were given the medicine escitalopram. Treatment lasted 12 weeks. Only 38 people had a clear response to treatment and clear PET scan results. In the psychotherapy group, 12 people got better and 9 did not. On their PET scans, those who did well had shown less activity in an area of the brain called the insula than those who did not improve. The insula is involved with emotion and self-awareness. Among those taking medicine, 11 got better and 6 did not. Those who did well had shown more activity in the insula. Many researchers are looking for better ways to choose the most effective treatments for depression. But authors of this study said PET scans are unlikely to have a practical role any time soon. The journal JAMA Psychiatry published the study June 12. MedPage Today and NPR.org reported on it.

By Mary Pickett, M.D.
Harvard Medical School

What Is the Doctor's Reaction?

To treat depression, you can start with medicines, psychotherapy or both. Some people respond better to one thing. Some people respond better to another. Depression improves within a month or two for about 40% of people who start treatment.

Now a small study suggests that brain scans might predict what treatment will work best for each person. The study looked at 63 people who had depression. PET scans were done before treatment was started. PET stands for positron emission tomography. This type of scan combines an injected radioactive chemical and a CT scan. It shows the body's organs as they work.

The scans showed that some people had more activity than other people in an area of the brain known as the insula. This area helps with psychological self-awareness, a feeling that you can make changes to improve your life. The insula also is involved in processing emotions. Researchers suspected it might relate to the way that people can manage their symptoms of depression.

After their brain scans, people were divided randomly into two groups. One group had psychotherapy ("talk therapy") sessions. The other group was treated with the antidepressant escitalopram (Lexapro). After 12 weeks, people were divided into those who seemed to get better and those who did not. Researchers compared these results with the PET scans.

People who already had a lot of activity in the insula didn't seem to benefit from psychotherapy. They did seem to have a good response if they were assigned to take the medicine. People who had less going on in the insula seemed to get better with psychotherapy. Medicines did not reliably help them.

Is this believable? Is it big news? The idea of using a scan to direct therapy sounds interesting to me. On the other hand, it sounds expensive and I am not sure it is going to help most of my patients.

I am a primary care doctor. Most patients who are ready to seek treatment for depression start by talking to me about it. And most of them have very strong ideas about which treatment they want to start first. In the study, all of the patients were randomly assigned to one kind of treatment or the other. If patients had been able to choose, would they have put themselves into the best treatment for their "brain type"? It would be interesting to know that.

What Changes Can I Make Now?

I think it is a big success when a person with depression decides to start treatment. The next checkpoint is to make sure that we are making good progress.

A couple of years ago, a study found that slightly over half of people with depression received treatment for it. Yet only 1 in 5 people got as much treatment as expert guidelines recommend. Most people who took medicines either stopped too soon or did not see their doctors often enough. Most people who began psychotherapy did not see their therapists often enough for this to help.

Either a primary care doctor or a specialist (psychiatrist or psychologist) can diagnose depression. When you first talk with your doctor, take the time to make sure that depression is the real cause of your symptoms. Make sure your doctor has checked for problems with thyroid function, sleep disorders and iron deficiency or anemia. These common medical problems can cause fatigue and low mood. Antidepressants are not the best way to manage depressed mood that is caused by substance abuse.

You can receive one or both of these treatments:

• Antidepressants: These are the most widely prescribed class of drugs in the United States. But many people who use them don't get treated long enough. Many people also don't see a doctor often enough to adjust the doses. Treatment with antidepressants should last at least two months. Most people with depression do best if they take medicine for 6 to 12 months. People with very severe depression may consider lifelong treatment.
• Psychotherapy: In 2005, nearly 1 out of 5 Americans with depression sought out psychotherapy. Two types are particularly helpful. Interpersonal psychotherapy helps you to sort out which people in your life support you and which are unreliable for you. It can help you to resolve stressful disputes and learn to take care of your own needs. Cognitive behavioral therapy teaches you to think positively, to solve problems and to rediscover simple pleasures.

When treating depression, it is best to have at least four visits each year with your primary care doctor or a mental health professional.

What Can I Expect Looking to the Future?

We don't know whether brain scans will become a useful and affordable tool to help guide treatment choices for depression. We are a long way off from that being a practical strategy.

Another future tool is genetics. We may soon be able to use gene tests to choose a dose or to predict what medicine is likely to work best for each patient. This kind of gene testing is called pharmacogenetics.