Depression

TMS For Depression: Everything You Need to Know

October 6, 2020

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There are many different forms of treatment for depression. This should come as no surprise since the World Health Organization lists depression as a leading cause of disability around the globe. With nearly 300 million people suffering from the disorder every year. Although there are a variety of effective treatments for depression, such as prescription medication and counseling, the disorder disrupts so many people’s lives around the world that there is no surefire cure that will be effective for everyone. As such, when the normal treatments like medication and psychotherapy are ineffective or ineffectual, many patients turn to alternative treatment methods for their depression. One modern and growing type of treatment is Transcranial Magnetic Stimulation (TMS). A type of treatment for depressive disorders that involves a lot less pharmaceuticals and prescription medications than the usual treatment regiment.

Photo of brain
By mapping the mind scientist know where to target their magnetic stimulation. Photo Courtesy of Midcity TMS

What Is Transcranial Magnetic Stimulation?

Magnets, Mental Health, and Modern Medicine

The earliest understanding of TMS came in 1881 when the English physicist Michael Faraday observed that a pulse of electrical current passing through a wire coil creates a magnetic field around the coil, and that this magnetic field could be influenced and manipulated by introducing another coil, or any other conductor of electricity, nearby. In the 1980s P. A. Merton & H. B. Morton first successfully stimulated the motor cortex of the brain using transcranial electrical stimulation (TES). 

However, the use of electrical currents was quite uncomfortable for the patients. The first person to begin exploring alternatives to TES Anthony Baker at the University of Sheffield in England in 1985. Due to the underlying physical connection between electricity and magnetism, Baker was able to surmise that in the same way that electricity stimulates the brain, magnetism might be able to do the same. By exploring how the use of magnetic fields influence the electrical signals and impulses in the brain, he was able to create the first function and stable Transcranial Magnetic Stimulation device.

However, the devices' therapeutic use, their use in psychotherapy and treatment of depression, wasn’t discovered right away. Early on the devices were really just used as diagnostic tools that would allow scientists to monitor the activity in different portions of the brain. In 1991 the journal Neurology published an article title Induction of Speech Arrest and Counting Errors With Rapid-Rate Transcranial Magnetic Stimulation by Alvaro Pascual-Leone. This article kicked off nearly two decades of research, clinical experiments, and conferences amongst the scientific community. The research continued to build and build, along with the scientific consensus. After it was discovered that TMS could be “leveraged for therapeutic applications in neurology, psychiatry and rehabilitation” the United States Federal Government approved the devices for psychotherapy in 2008. 

Scrabble blocks
Mental health issues are the leading causes of disability in the United States.

How Does TMS Work for Depression

Excite Enervated Neurons With Targeted Magnetic Fields 

TMS is a non-invasive and safe neuromodulatory and neurostimulator technique that was initially used as a diagnostic and research tool by neuroscientists. However, upon realizing that it could be used to “transiently or lastingly” modulate the “cortical excitability of neurons,” it was determined that there could be neuropsychological techniques developed that could be used to treat those suffering from mental illnesses. The cortical excitability of a neuron is the neuron's response to stimuli, as well as the activity level it is functioning at. By using magnetic waves to intervene and influence the cortical excitability of different portions of the brain, scientists are able to achieve different temporary or enduring responses in their patients' neurochemistry. This is done because the underlying connection that magnetism shares with electricity that we mentioned earlier. By targeting magnetism at certain centers of the mind, scientists can manipulate the electrical charge that is the underlying axiom that powers human intellect.

TMS has shown the potential to be a promising treatment for a whole host of different medical issues. In particular it has shown promise as a treatment for a myriad of neurological conditions such as Alzheimer’s disease, epilepsy, and schizophrenia. It has also been shown to be an effective tool in psychiatry. It has been used as an effective treatment when dealing with anxiety and depressive disorders such as major depressive disorder (MDD), bipolar disorder (manic depression), and treatment-resistant depression (TRD).  By going directly to the electrical currents that power the mind itself, doctors have found it a useful tool when medications are ineffective.

The same way that the pharmaceuticals and prescriptions that are used to treat depression are designed to target specific areas and functions of the brain in order to alleviate the patient’s symptoms, TMS is targeted in the same way. By manipulating the magnetic fields arounds the different portions of the brain, psychiatrists and doctors are able to specifically target the segments of the brain that are responsible for the symptoms the patient is suffering from. In the case of depression this is done by focusing the magnetic wave to influence the cortical excitability of the neurons in the portions of the brain that have decreased neurological activity.

Given the rapid advancements in mankind's ability to map and observe the human mind, scientists have been able to discover with much more specificity which portions of the brain are responsible for regulating different moods and emotions. By specifically targeting these areas of the brain with the magnetic fields, scientists and clinicians are able to increase or decrease the sensitivity of those areas and affect changes in mood as a result. The manipulation of the brain's electrical connections with magnetic pulses has been shown to have a positive effect on the brain’s production of neurotransmitters. 

These neurotransmitters are what allows the brain to communicate with other parts of the brain so the entire cellular structure can work together in tandem. When one portion of the brain's production of neurotransmitters falls at a rate that is non commensurate with the other portion of the mind, miscommunications happen. The increase in the production of neurotransmitters, as well as the increase in neurological activity, can lead to long term remission of a patient’s depressive symptoms because it allows the different parts of the patient's mind to communicate with each other the way they are supposed to.

When TMS is used for the treatment of Depression it is usually focused on the patient’s left dorsolateral prefrontal cortex (DLPFC). The prefrontal cortex is a portion of the brain that controls a person's “executive functions.” Executive functions is a term used by psychologists, psychiatrists, and neuroscientists that includes a person’s ability to distinguish between ideas, actions that can or should be taken. As well as the different outcomes that can or will result from those different ideas and actions. The prefrontal cortex is broken up into different areas all with their own specialized tasks and activities that they perform. The dorsolateral section of the prefrontal cortex is  responsible for creating a person’s emotional responses and reactions to different people, places, and events. 

While it is true that the scientific literature shows that depression is strongly associated with activity across the entire brain decreasing, the prefrontal cortex shows an even greater decrease in activity than the rest of the brain when a person is suffering from depression. And the dorsolateral section of the brain shows an even stronger decrease in activity during depression than the rest of the prefrontal cortex does. Given that the dorsolateral section of the brain shows the most decrease in activity of any section of the brain when a person is suffering from depression, scientists have determined that the lack of activity in that portion of the prefrontal cortex is what causes depression at a biological level.

By focusing the magnetic waves on the dorsolateral prefrontal cortex, doctors are able to increase the cortical excitability of the neurons within that section of the brain. By increasing not only the excitability of the neurons in the dorsolateral section, but also increasing the production of the neurotransmitters the dorsolateral section, and prefrontal cortex as a whole, need to perform their proper functions, it is possible to cause a significant change in a patient’s anxiety, depression, and moods. 

By restoring the dorsolateral section, and to a lesser extent the prefrontal cortex itself, to the appropriate levels of cortical excitability and activity, scientists are able to restore that part of the brain back to the original, or to an improved level of function. By increasing the function of the portion of the brain that handles emotions back to normal, depressive symptoms are able to be reduced at a neurochemical level. 

Diagram of TMS
By focusing magnetic waves on the dorsolateral section of the brain scientist can manipulate neural excitability. Photo Courtesy of Williamsville Psych

Should You Consider TMS for Your Depression?

Tired of Treatments You’ve Been Resistant To?

If you have tried the standard treatments for depression, such as medication and psychotherapy, and haven’t received the desired results, you may want to look into scheduling TMS therapy with your doctor. Those who do not show improvement in their symptoms after undergoing standard depression treatment are considered to have treatment-resistant depression. Studies have shown that for the people with major depression symptoms that don’t benefit from medication, just over half of them experience improvements in their symptoms with TMS. While almost one in three gain long term or permanent remission from their depression symptoms. 

There are several significant and consequential studies or interviews that lend support to the use of TMS as treatment for depression. These include The Carpenter Study, The Dunner Study, the Benjamin Testimonial, and the Sharon Gray Testimonial. The Carpenter Study, published in Depression and Anxiety in 2012 included 42 TMS sites and over 300 patients. Almost 60% of the patients saw relief from their depressive symptoms and over one third saw complete remission. In 2014 The Dunner Study observed over 257 patients and found that repetitive TMS treatments were effective for those suffering from treatment resistant MDD and that the effects would last up through at least one year. 

There’s still plenty of research to be done. And it's not entirely understood exactly how to best use TMS in treatment. Clinicians still don’t know the exact frequency that is most effective. Or what intensity of magnetism is the most efficient at causing the desired outcome. It’s also unknown precisely which patients are likely to be the most receptive to TMS treatment and who it will be the least effective for.

However, you should be aware that there are some side effects associated with the treatment. The most common side effects are headache, scalp discomfort at the area the magnets were placed, a tingling, twitching, or spasming of face muscles, or lightheadedness during and after the treatment. Some rare but serious side effects also exist and these include seizures, mania (especially in those undergoing treatment for bipolar disorder), and hearing loss if the patient's ears are inadequately protected during the treatment. 

While these side effects are rare, you should discuss them with our doctor beforehand. You should also tell your doctor if you are pregnant, have any metal or implanted medical devices in your body. The treatment is not recommended for those who have any type of metal in their body, This includes everything from hearing implants and stents, to bullet fragments and pacemakers. Due to the treatment being based around magnetism and magnetic waves, any metal in the body can suffer from the pull of the magnets. This could cause a significant amount of irritation for the patient as well as even some pretty serious damage to the body itself. The same way that electricity is influential on magnetic fields, magnetic fields are influential on electricity. As such electronic devices like pacemakers and pumps are liable to be disrupted or disable by the production of string magnetic weaves that are involved in the procedure. So make sure you go over everything thoroughly with your doctor beforehand.

Doctor and patient's feet
Be sure to have a thorough discussion with your doctor before planning any new treatment plan.

TMS has shown the potential to be the future of depression treatment. With so many people reporting total remission of their symptoms its worth looking into for anyone suffering from the disorder. 

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