‘Pacemaker for the brain’ makes untreatable depression treatable

This could be the breakthrough psychiatry has been waiting for for years.

Unfortunately, depression is a common problem. Fortunately, a psychologist or psychiatrist can often help. But for a small proportion of patients, behavioral therapy or medication are not enough; they suffer from severe and untreatable depression. So is Sarah (whose last name is omitted at her request). “I was at the end of my rope. I was very depressed (…) This was not a life worth living.” But thanks to the work of researchers at the University of California (San Francisco), her situation has changed abruptly and radically. After years of unsuccessful treatments, her depressive symptoms have finally eased. “At first the emotions and the darkness were overwhelming, but now I get up and just go about my day.”

Pacemaker
It’s all thanks to a tiny device implanted in her brain that – when needed – stimulates a specific part of her brain. A kind of pacemaker, but for the brain.

Deep brain stimulation
This is not the first time that researchers have used so-called deep brain stimulation in an attempt to reduce or remedy depressive symptoms. But previous attempts were only limited or varyingly successful. This has to do with the fact that most brain implants used for this purpose continuously emit electrical signals and can often only be used in one brain region. The latter is inconvenient, because the areas of the brain that produce depressive symptoms can differ from person to person.

Customization
Reason enough for American researchers to develop a different approach. The result is a brain implant that only stimulates the brain when it is really necessary and also focuses on a brain region where stimulation has the greatest positive effect on the mood of the patient in question (see box).

As mentioned, depressive symptoms in one person can arise from different brain areas than in the other. For effective deep brain stimulation, intended to remedy depressive symptoms, you must therefore determine for each patient which brain area responds best to stimulation. The researchers established this by placing ten electrodes in different brain areas and taking turns mildly stimulating those brain areas and seeing how the patient responded. In Sarah’s case, stimulation of the ventral striatum was found to improve mood the most. And with that, the researchers had found a brain region that they could stimulate. But they preferred to stimulate that brain area only when it was really necessary, namely when her mood threatened to deteriorate. And that too is possible. The researchers have shown that the emergence of depressive symptoms coincides with a specific pattern of brain activity that is particularly measurable in the amygdala. The researchers then developed a brain implant that continuously measures brain activity in the amygdala and, as soon as the abnormal pattern is detected, stimulates the striatum ventrale.

The results are impressive. “We were able to offer this tailor-made treatment to a patient with depression and relieve her symptoms,” said study researcher Katherine Scangos. And where it can take weeks after standard treatments for the depressive symptoms to subside, Sarah noticed almost immediate results. Not only shortly after the implant, but also in the fifteen months that have passed since the implant was placed. “In the first few months, the depression eased so abruptly that I wasn’t sure it would stay that way,” Sarah said. “But it has remained that way. And I’ve come to realize that the device enhances the therapy and self-care I’ve learned to practice.”

Future
The hope is, of course, that many more people with ‘untreatable depression’ can be treated in the future. “The idea that we can treat symptoms as they arise is a whole new way of tackling the most difficult cases of depression to treat,” said Scangos.

But more research is needed before this treatment can be rolled out widely. The clinical trial is currently being expanded to include two new patients and hopefully nine more will follow soon. The follow-up study should show whether the approach also works as well and for a long time for others. Scientists also hope to gain even more insight into the brain regions involved in depression. This may also lead to completely new treatments in which the activity in these brain regions can be adjusted in a less drastic way.

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