Depression can strike anyone. No matter how successful you are. No matter how rich or famous you are. It doesn’t care if you’re physically healthy or if you’ve never suffered trauma or tragedy.
It might start with apathy and numbness. Then, you begin ruminating more and more. Your brain magnifies your little mistakes, turning them into mountains. You lose your will to get up out of bed in the morning. You stop seeing your friends, you can’t handle going out. Before you know it, depression takes over your life.
Depression affects more than 250 million people worldwide. Despite decades of research, depression is still hard to understand and treat. Many people don’t respond to the first medication they try. If they do, it takes several weeks and unpleasant side effects.
The recent decade brought new treatments to the mainstream. Ketamine received approval for treatment-resistant depression and psilocybin is well on its way. Still, many people experience depression and react to treatments differently.
Even ketamine and psilocybin will face these hurdles and tribulations. After all, there are so many networks and systems in the brain and body that go awry. It’s unlikely that one antidepressant drug would treat all cases of depression.
Why Haven’t We Zapped Away Depression?
Repetitive transcranial magnetic stimulation (rTMS) is a non-invasive treatment approved in 2008. Using a coil placed near the scalp, magnetic waves pulse and pass through the skull. These waves stimulate specific brain regions, alleviating symptoms of depression.
When antidepressant medications and psychotherapy don’t do the trick (or need a helpful boost) rTMS is invaluable. It works quickly, without many side effects.
rTMS is only effective in around 29% of cases and with a 19% remission rate. The majority of people who try rTMS as a potential last resort don’t receive relief. We can attribute a lack of efficacy to the brain being extremely complicated. In each individual, different regions of the brain may contribute to depression. We don’t even understand how rTMS works to relieve depression.
If we want to zap our depression away, we’ll need to understand what the brain is or isn’t doing. Unfortunately, we can’t stick someone into a brain-scanning machine while zapping them. A lot of scanning methods involve strong magnetic and electrical fields. This will no doubt make it a lot harder to tell what’s going on.
Improving How We Zap
A new study used a method called Diffuse Optical Tomography (DOT) to image the brain during rTMS. DOT relies on the way that our body scatters and absorbs near-infrared light.
It can detect which regions of the brain are active by looking at blood oxygen. It tells clinicians which areas of the brain have red-blood cells carrying oxygen. This information is then used to create a high-resolution 3-D image of the brain over time. Here, researchers showed that DOT measures changes in the brain during rTMS safely and reliably.
The researchers examined six healthy controls and seven people with depression. They received rTMS targetting the brain’s left dorsolateral prefrontal cortex, implicated in depression. In depressed individuals, the brain’s response was less robust and took longer to reach its peak. Thus the FDA standard protocol isn’t adequate for many patients with severe depression.
The team behind these findings hopes to initiate clinical trials to validate these early results. Since DOT is inexpensive, small and portable, it will become easier for clinicians to personalize zapping to each individual. Perhaps in a decade, rTMS might be able to treat many more cases of severe depression.