Deep Magnetic Brain Stimulation An Experimental Treatment for Depression
Dr. Abraham Zangen, Weizmann Institute of Science
Dr. Yiftach Roth, Brainsway Ltd.
Severe, chronic depression is a psychiatric disorder that plagues the lives of millions of people. Most receive psychological treatment, medication, or a combination of the two. Many others, however, find no relief from these forms of treatment. Until recently, the only recourse for these people has been electroconvulsive therapy (ECT), more commonly known as electroshock therapy, a controversial method that requires the use of general anesthesia.
In recent years, however, scientists have been developing instruments that magnetically stimulate the brain through the scalp. The new method is called transcranial magnetic stimulation, or TMS. Magnetic stimulation of the brain is non-invasive, painless, and requires no anesthesia. It has therefore sparked the interest of researchers who are testing its use for the treatment of psychiatric and neurological disorders. One of the drawbacks of most TMS devices developed so far is their limited range of influence, which extends to no more than two cm deep into the brain. Therefore, they have no effect on structures that lie within the depths of the brain's cortex, and underneath it, including those connected with emotions, pleasure, and reinforcement. Now, thanks to innovative work conducted here in Israel, in cooperation with the Weizmann Institute for Science, TMS is effectively targeting areas further within the brain, reaching a depth of 5-6 cm.
A start-up company, Brainsway, was established in Jerusalem in 2003 to further develop this new device, and its team of engineers has been working ever since to perfect its functioning. The development of the new technology also involves laboratory experiments with animals and clinical trials on patients in psychiatric hospitals.
Map of the electric fields in a brain model as a reaction to magnetic stimulation
The Research Questions
Does deep magnetic brain stimulation treatment help people who suffer from depression?
If the treatment produces a positive response, how intense is this response, how soon does it occur, and how long does it last?
The Research Methods
To answer the research questions, scientists conducted clinical trials at the Shalvata Mental Health Center to measure the effect of deep TMS treatment on patients who suffer from a form of depression that is resistant to medication.
Prior to the clinical study with patients, scientists first conducted two sets of tests to ensure the safety of the device and rule out any possibility of negative cognitive or emotional side effects. The first tests were performed on laboratory animals, and only when safety was assured, trials were conducted on healthy human beings.
Each patient participating in the clinical trials received TMS treatment five days a week over the course of four weeks.
To assess the effect of the treatment, a physician interviewed the patients every few days using a standardized questionnaire for identifying symptoms of depression. (The higher the rating on the questionnaire, the more severe the patient's depression.) In addition, the patients themselves were to asked to report their feelings using standard questionnaires.
The findings were encouraging: About half the patients treated were ranked at least 50% lower on the "depression scale," and only 8% showed no improvement.
For most patients, positive effects were apparent after only 7-10 days of treatment and lasted for a week after the treatment ended.
In a follow-up exam three months after completion of the treatment, researchers found that the condition of most patients who had responded positively did not deteriorate.
The patients did not report any negative side effects or signs of addiction.
Discussion and Conclusions
This research was conducted using innovative technology for the treatment of severe depression that is resistant to medication.
The researchers' breakthrough was to expand the range of magnetic stimulation to areas deep within the brain that are related to depressive disorders.
While the results are encouraging, they point to a long road ahead before this experimental treatment becomes an accepted, widely used method for treating depression. Further research is needed, for example, to examine the long-term effects of the treatment.
By configuring the magnetic coils in different ways, the system's developers hope to be able to treat a variety of conditions that, like depression, require stimulation of regions deep within the brain: drug addiction, obesity, Parkinson's disease, and Alzheimer's disease, to name a few. Initial research in these areas is already under way.
Importance of the Research
A breakthrough in treatment for depression is highly significant for the millions of people who suffer from this condition, particularly for those who fail to respond to existing forms of treatment or choose not to undergo them. Effective treatment for severe depression will not only vastly improve quality of life; in many cases, it may even save lives, given the high percentage of patients with major depression who attempt to commit suicide.
The success of TMS in treating depression will serve as a model for developing non-invasive, non-pharmacological treatment for many neurological and psychiatric disorders whose source can be localized in particular areas of the brain.