You may have read last month of a helmet that you can use at home (but not yet) for treating your depression.
The stories, including this BBC account, all center around the research of Steen Dissing, who specializes in cellular and molecular medicine at the University of Copenhagen.
According to a study he and his colleagues published in April in Acta Neuropsychiatrica, 65 treatment-resistant patients (many still taking antidepressants) were pulsed with the helmet - half of them once a day, the other half twice a day - for 30 minutes. After five weeks, about three in ten of the patients in both groups achieved remission. After eight weeks, the figure shot up to about seven in ten.
By way of comparison, about half of the subjects receiving the test drug in antidepressant clinical trials typically achieve "response" after about six weeks. Response (a reduction in symptoms by half) is a much lower threshold than "remission" (where the patient is virtually symptom-free).
According to a BBC News report of the study, one patient reported: "The fog lifted. ... It was like someone hit the reset button - and I was back to normal."
The helmet contains seven coils that send electromagnetic pulses into the brain. The treatment is called Transcranial Pulsating Electro Magnetic Fields (T-PEMF). On the surface, T-PEMF appears very similar to TMS or rTMS treatment, which also involves the use of coils. In 2008, the FDA approved rTMS for treating major depression on patients who have failed on at least one antidepressant.
A 2010 meta-analysis of 34 trials found rTMS to be about as effective as antidepressants in treating depression.
rTMS has been promoted as a less risky alternative to ECT. In rTMS, the pulse is thought to have the effect of depolarizing or hyperpolarizing targeted neurons in the outer frontal cortical regions. In essence, rTMS may be normalizing electrical currents in the brain.
Many commentators view PEMF as a form of TMS, which may be true, but Dr Dissing has a different explanation, and here things get really interesting.
PEMF was first used by veterinarians back in the 70s for helping heal broken bones in animals. Then sports doctors began experimenting off-label on their athlete-patients. A host of non-approved devices (such as mats or pillows with coils) have been on the market for years. In 2004, the FDA approved PEMF as an adjunct to cervical fusion therapy.
The theory is that PEMF activates capillaries to form new blood vessels. This is known as angiogenesis, which is a natural process in the healing of wounds and the formation of new tissue. Runaway angiogenesis, though, is associated with cancer.
According to Ron Duman of Yale, in a 2004 article, angiogenesis may be linked to neurogenesis. This is currently a hot topic in the field of strokes.
Neurogenesis refers to new brain cell growth. One may also stretch the meaning to include restoring damaged cells to normal. Key to this are various protein growth factors, such as brain derived growth factor (BDNF).
Back in the early 2000s, Dr Duman discovered that lab animals who were administered antidepressants experienced brain cell growth in the hippocampus. From this, Dr Duman and others hypothesized that antidepressant medications may work by indirectly inducing new brain cell growth.
This is a long way from explaining how an electromagnetic pulse may activate angiogenesis in the first place, but assuming it does, we can conceptualize the following chain of events: The formation of new blood vessels, the release of various growth factors, brain cell repair, restoration of key neural networks, normalized brain function, no more depression.
We should not confuse Dr Dissing's small pilot study with a large-scale clinical trial. In psychiatry, clinical trials invariably fail to replicate the promising results of the pilot study. And a spectacular result in a small study inevitably translates at best into a ho-hum result in a much larger one.
You never know. Let's wait and see.