Treatment resistant depression is one of the most crippling and emotionally devastating conditions known to man. The loss of hope in ever recovering from a disease that does not respond to conventional treatment and has hopelessness as one of its symptoms can lead to a deadly downward spiral. Many good medications have been developed to treat Major Depression over the years, but sometimes the disease can be too severe and the medicine does not work. Some intensive treatments, such as ECT, are very effective but have severe side effects. This leaves many patients seeking a better solution. This dire need for a better solution led to the development of TMS.
So what exactly is TMS? TMS is the acronym for Transcranial Magnetic Stimulation, which is a cutting edge treatment for depression that involves stimulation of brain tissue using electromagnetic pulses. This noninvasive procedure improves symptoms of depression by activating the parts of the brain associated with mood control and depression. TMS has grown in popularity due to the high degree of effectiveness while having very few side effects and absolutely no circulation of medication in the bloodstream. The process starts with the placement of an electromagnetic coil over the scalp near the forehead. The motor strip, the area of the brain responsible for movement of limbs and muscles, is then mapped out. This is necessary in order to subsequently determine the location of the lateral pre-frontal cortex. The actual procedure involves delivering a sequence of magnetic pulses to the left lateral pre-frontal cortex to induce stimulation. The magnetic pulses pass through the scalp and the skull to reach the target brain tissue. TMS activates the actual neurons by inducing an electrical current in the part of the brain cell called the axon. This current travels to the nerve cell body and then affects other connecting brain cells. This stimulation ultimately creates the powerful antidepressant effect. TMS is indicated when conventional treatments for Major Depression have not worked. TMS is also an option for individuals who suffer from Major Depression and do not wish to take medications. TMS was approved by the FDA for the indication of treatment resistant depression in 2008. Deep TMS, possible with the newer generation of TMS technology, was approved by the FDA for the indication of treatment resistant depression in 2013.
Deep TMS, also known as dTMS, refers to a more deeply penetrating form of TMS now possible using the newer generation of TMS technology produced by the Brainsway Corporation. Brainsway has engineered the H1 dTMS coil that was approved by the FDA for the indication of Treatment Resistant Depression. The H1 coil produces a magnetic pulse that stimulates a larger area than a traditional figure 8 coil. The stimulation also penetrates deeper, reaching 1.7cm into the cortex. The benefits of this have to do with both a more complete stimulation of the target area as well as some stimulation of the neighboring areas of the brain that interconnect with the target area. The risk of dramatically losing efficacy from deviating even just 1mm from the target area is greatly diminished using a Brainsway device, as compared to a traditional figure 8 coil, due to the larger and deeper area of stimulation. The treatment session consists of up to 2,500 pulses delivered over a time span of approximately 20 minutes. This all helps yield higher rates of both response and remission of Treatment Resistant Depression.
So we have seen what TMS can do, as far as having very high response and remission rates in severe grades of depression. What is TMS like though? The very first step is proper screening and evaluation. TMS has an FDA indication for Treatment Resistant Depression, although many practitioners have reported even better results in the non-resistant grades of Major Depression. Individuals do have the option of receiving TMS for a non-resistant grade of Major Depression, as an off-label usage of this medical technology. Insurances will only cover the FDA indication for Treatment Resistant Depression though.
Treatment Resistant Depression is most commonly defined as a Major Depressive condition that has not responded to at least 4 different antidepressants, including medications from more than 1 antidepressant category. Appropriate candidates would also have not responded to one or more “augmentation” strategies, which is when a secondary medication is added to boost the effect of the primary medication. Appropriate candidates commonly also would have failed a course of psychotherapy. Some may have also even failed ECT. A medication “failure” is defined as not achieving an adequate response after reaching the maximum dose for at least 4 to 6 weeks, or not being able to tolerate the medication at any point in the dosing range. A “response” is most commonly defined as a 50% reduction in symptom intensity based on depression rating scales. Most people will appropriately determine a medication non-response by simply recalling that it did not make them feel much better. An antidepressant that once worked but at some point stopped working would also constitute a failure. Others, again, simply could not tolerate a medication due to side effects. Some cannot tolerate a medication at all, at any dose. Some cannot tolerate a medication at the dose that it would take to get it to work. Either way, it is considered a medication failure. After a patient has been determined to have actual Treatment Resistant Depression, the next step is to make sure there are no medical conditions that are TMS exclusions.
TMS is a very safe and tolerable treatment with few medical exclusions. There are some conditions that not compatible with TMS though, and these must be screened for. The first situation is the presence of any metal in or near the head or any implanted medical devices. Examples include cochlear implants, implanted electrodes/stimulators, aneurysm clips or coils, stents, bullet fragments, jewelry and hair barrettes. Any metallic object within the magnetic field would be at risk for overheating or possibly moving. Implanted medical devices risk malfunctioning. Other exclusions include any history of aneurysms, seizures, stroke, brain surgery, neurologic disorders, and active substance abuse. Once a patient has been evaluated and screened for appropriateness for TMS, they can start treatment.
The first stage of treatment consists of mapping the brain to find the best treatment location. This is usually done on the very first session, which in total takes about an hour. Certain physical landmarks are identified on the head, specifically the nasion and the inion. The nasion is the distinctly depressed area directly between the eyes, just above the bridge of the nose. Inion is the bony prominence on the back of the skull. These landmarks and the nasion-inion distance are used to locate the starting point for locating the motor strip. The motor strip is the part of the brain responsible for controlling muscular movements. A significant portion of the motor strip represents the thumb and hand, which triggers thumb movement when stimulated at a specific location by a TMS machine. This location is used to determine how much energy is needed to elicit a muscular (in this case thumb) movement, which is the “motor threshold”. Treatment intensity is usually 120% of the motor threshold. This location also serves as the orientation point for the treatment location, which is 6cm towards the front of the brain. These measurements are all recorded on a fitted cap that is specific for each patient. Once the mapping and motor threshold determination phase is complete, treatment can begin.
The first Deep TMS treatment session starts at 100% of the motor threshold, to allow the patient to acclimate to the treatment before going to a higher dose. The 100% dose is generally easier to tolerate than the target 120% dose. If the dose is gradually increased from 100% to 120%, most patients will acclimate well. Patients often describe a tapping sensation on the scalp, in addition to the sound of the electromagnetic pulse generation. The sound is similar to that of an MRI machine and is managed well with earplugs. The tapping sensation is generally tolerable. Some people may also experience headaches in the earlier stages of treatment, which is typically resolved with either ibuprofen (Motrin) or acetaminophen (Tylenol). Many patients report a significant reduction in these side effects after even just the first TMS session. Seizures, the most severe potential complication of TMS treatment, are very rare. Most patients acclimate well to the early stage side effects and can proceed with treatment.
A typical Deep TMS treatment course will consist of at least 5 days a week for 4 weeks, followed by 2 days a week for 8 weeks. Another common treatment course starts with at least 5 days a week for 6 weeks, and then the frequency tapers down from there. The recommended minimum number of treatments is 36 while some TMS courses can have as many as 42 or more. Some patients will note an early response in the first 3 to 4 weeks but many will take at least 6 weeks to really derive substantial benefits. Many of the patients that did not get a response within 6 weeks still derive a good response later in the treatment course, indicating the need to follow through with at least 36 treatments. After a successful course with 36 to 42 treatments, some may not require any further treatment while others may need short booster courses of 3 to 6 treatments a few times a year. Overall the success rate is very high.
In depression treatment, success is defined by rates of response and remission. It is important to note that in TMS studies, the patient population is a “treatment resistant depression” population that has failed 4 or more medications already. This population would be expected to have a significantly lower response rate to any type of therapeutic intervention than a conventional depression case. Even taking that factor into consideration, Deep TMS response rates after 30 sessions have reached 74% while full remission rates reach 49%. In comparison to other forms of depression treatment, these are extraordinarily high rates. Anecdotal reports suggest that response rates in non-treatment resistant depression patients are even higher. This supports the growing belief that TMS may one day become a first line treatment for Major Depression. Patients have increasingly asked for TMS to treat their depression before waiting to fail on 4 different medications. With the unequivocal results, an exceptional side effect profile, and the ability to produce long-standing brain changes through induction of neuroplasticity, this is no surprise. This is why Deep TMS has become the great new hope for treatment resistant depression.
Dr Rodriguez is the founder, CEO and Medical Director of the Delray Center For Brain Science, a true Brain Center which specializes in Treatment Resistant Depression, ADHD, OCD, Memory Disorders, and optimizing brain performance.
Since 2003, the Delray Center for Healing has provided exceptional psychiatric and therapeutic care for mental health, eating, and substance use disorders. To learn more about our philosophy and treatment approach, download our free e-book, “Psychiatry Redefined,” written by our founder and medical director, Raul J. Rodriguez, MD.