Major depressive disorder, or clinical depression, is a mental condition that knows no bounds; it affects more than 300 million people spanning all races, ages, genders, and communities and its global burden is likely to increase with time (Somani and Kar, 2019). That said, numerous treatment modalities exist, but nearly 30% of clinically depressed patients do not respond to treatment (Basil, et al., 2005). To tackle this challenge, researchers are now looking toward transcranial magnetic stimulation (TMS), a neuro-experimental tool that can induce neural excitability and help us understand the physiology and connectivity inherent to clinical depression (Somani and Kar, 2019).
Clinical depression is a highly prevalent psychiatric disorder that is characterised by persistently low mood, feelings of worthlessness, lack of energy, or suicidal thoughts (Bains and Abdijadid, 2022). Despite its pervasiveness, clinical depression is still difficult to treat as standard treatment approaches such as psychotherapy, medications, or a combination are often inadequate and patients become treatment-resistant (Janicak and Dokucu, 2015). This creates a significant gap in our ability to effectively limit clinical depression-related symptoms, leaving patients vulnerable to ensuing substance abuse, suicide, or employment-related complications.
In order to improve outcomes for patients with treatment-resistant clinical depression, the novel neuromodulation technique TMS has been explored (Janicak and Dokucu, 2015). Approved by the Food and Drug Administration in 2008 for treatment of clinical depression, TMS is a non-invasive nerve stimulation treatment that applies electrical currents to induce short- and long-term changes to a patient’s behaviour (Rizvi and Khan, 2019).
The physics principle governing the application of TMS is Faraday’s Law of Electromagnetic Induction, which states that every electric current is surrounded by a magnetic field and alternating currents produce fluctuating magnetic fields (Sauvé and Crowther, 2014). Fluctuating magnetic fields in turn generate electric current to flow in nearby conductors; the conductors in this case being neurons within the brain. In so doing, TMS, without any intrusion into the skin, muscles, or bones, electrically stimulates the brain to alleviate depressive symptoms, as seen in Figure 1 (Rizvi and Khan, 2019).
Figure 1: Pictorial representation of the underlying physics concepts behind TMS. Faraday’s Law of Electromagnetic Induction states that an electric current (black ring) flowing through a coil creates a magnetic field (green dashed line) that is perpendicular to that current. When the coil is placed in close proximity to a nearby conducting medium, for these purposes, human tissue, the magnetic field induces a current in the opposite direction (red line) of the original current in the coil. During treatment, the device containing a coil is held over the skull near a region of interest to cause changes to neuronal activity and modify a patient’s behaviour. As a result, TMS is able to safely, painlessly, and non-invasively stimulate the brain to treat clinical depression (Holvoet, 2015).
Conventional TMS treatment involves repetitive delivery of electromagnetic pulses at a single frequency over the dorsolateral (DMPFC) and ventromedial (VMPFC) prefrontal cortices, shown in Figure 2 (Sauvé and Crowther, 2014). In clinical depression, these specific structures exhibit hypoactivity, impaired connectivity, and lower glucose and oxygen metabolism at rest (Lan, et al., 2016). By mechanisms that are not well understood, high frequency stimulation (>5 Hz) of the DMPFC and VMPFC induces excitatory effects to neurons within the limbic system, directly alleviating symptoms of clinical depression (Sauvé and Crowther, 2014; Peng, et al., 2018).
Figure 2: Pictorial representation of the portions of the brain involved in TMS treatment. During a treatment session, the physician will place the magnetic coil near the ventromedial prefrontal cortex (VMPFC) to activate neurons in this region. Due to the deep roadway of neurons connecting the VMPFC to the inner brain, a patient’s hypoactive limbic system is energised. The limbic system includes the amygdala, hypothalamus, and striatum, and is responsible for controlling emotion. Activation of these three structures promotes feelings of relaxation, joy, and happiness for a patient. A typical TMS treatment stimulates these same neural pathways tens of thousands of times, strengthening a patient’s ability to think positively in the long-term (Fitzgerald, Cassidy and Rege, 2022).
Although explaining DMPFC and VMPFC excitability during TMS treatment is complicated, long-term potentiation has been hypothesised as the process behind this phenomenon (Sauvé and Crowther, 2014). To explain this more clearly, consider this: while one positive thought will activate a positive neural pathway exactly one time, a conventional TMS treatment will activate that same positive pathway tens of thousands of times, wiring the brain to think in a more positive manner. Over an extended period of TMS treatment, patients will strengthen synaptic connections in their brain and create an enhanced positive response to certain stimuli in the future.
Recent studies have celebrated the safety and efficacy of TMS and how it can successfully address the issues patients face with regards to treatment resistance (Rizvi and Khan, 2019; Janicak and Dokucu, 2015). As the field of brain stimulation advances, it could provide psychiatrists with the groundwork for 21st century practice. Researchers are right to be optimistic about TMS and the potential impacts it could have on the brain and neuropsychiatric care as a whole.
References:
Bains, N., and Abdijadid, S., 2022. Major Depressive Disorder. Treasure Island: StatPearls Publishing.
Basil, B., Mahmud, J., Mathews, M., Rodriguez, C. and Adetunji, B., 2005. Is There Evidence for Effectiveness of Transcranial Magnetic Stimulation in the Treatment of Psychiatric Disorders? Psychiatry (Edgmont), 2(11), pp.64-69.
Fitzgerald, P., Cassidy, T. and Rege, S., 2022. Transcranial Magnetic Stimulation (TMS) for Depression – Review of the Evidence. [online] Available at: <https://psychscenehub.com/psychinsights/transcranial-magnetic-stimulation-for-depression/> [Accessed 23 November 2022].
Holvoet, L., 2015. A DTI-based tractography research exploiting the brain network for object recognition and comparison with a TMS Speech Mapping experiment. In: Ghent University, Master of Science in Electromechanical Engineering Defence Thesis. Ghent, Belgium, 1-6 June 2015. Ghent: Belgium
Janicak, P.G. and Dokucu, M.E., 2015. Transcranial magnetic stimulation for the treatment of major depression. Neuropsychiatric Disease and Treatment, 11, pp.1549-1560. https://doi.org/10.2147/NDT.S67477.
Lan, M.J., Chhetry, B.T., Liston, C., Mann, J.J. and Dubin, M., 2016. Transcranial Magnetic Stimulation of Left Dorsolateral Prefrontal Cortex Induces Brain Morphological Changes in Regions Associated with a Treatment Resistant Major Depressive Episode; an Exploratory Analysis. Brain stimulation, 9(4), pp.1-29. https://doi.org/10.1016/j.brs.2016.02.011.
Peng, Z., Zhou, C., Xue, S., Bai, J., Yu, S., Li, X., Wang, H. and Tan, Q., 2018. Mechanism of Repetitive Transcranial Magnetic Stimulation for Depression. Shanghai Archives of Psychiatry, 30(2), pp.84-92. https://doi.org/10.11919/j.issn.1002-0829.217047.
Rizvi, S. and Khan, A.M., 2019. Use of Transcranial Magnetic Stimulation for Depression. Cureus, 11(5), pp.1–4. https://doi.org/10.7759/cureus.4736.
Sauvé, W.M. and Crowther, L.J., 2014. The Science of Transcranial Magnetic Stimulation. Psychiatric Annals, 44(6), pp.279–283.Somani, A. and Kar, S.K., 2019. Efficacy of repetitive transcranial magnetic stimulation in treatment-resistant depression: the evidence thus far. General Psychiatry, 32(4), pp.1–8. https://doi.org/10.1136/gpsych-2019-100074.
Comments
13 Responses to “A New Hope to Beat Depression”
Hi iSci!
Depression is a serious issue that affects so many people. Since I have been hearing a lot about depression recently, I decided to do some reading on innovative treatment methods for depression and I was intrigued by the technique of transcranial magnetic stimulation (TMS). What I found was very interesting. TMS is a promising procedure that uses magnets to change someone’s emotional pathways and can be used to treat patients that are resistant to psychiatric medications. This material is an application of the fundamental electricity concepts learned in first-year physics and basic neural anatomy from the neuroscience RP in second-year. If you have any suggestions for how I can improve this draft, please comment below. Thank you very much for reading.
Have a great day!
Rith
Hello Rith,
This was a remarkably well written post, and very engaging to read. I would just like to recommend a few small edits for improved flow.
1. I would use a different word in sentence 1 paragraph 1 instead of “sees”, potentially using the word “has” or “knows” instead. These words create a more natural sentence flow, in my opinion.
2. In Figure 1, you do not need to reiterate the expanded form of TMS, as it has already been explained prior.
3. Some of your statements are redundant, for example you mention the non-invasive modality of TMS treatments twice. You also mention depression as a “mental illness” and then a “highly prevalent psychiatric disorder” later on . I would recommend recommend removing one of these instances, as you mention it as a disorder twice in two different terms, and also reiterate its global prevalence twice. This word count could be better attributed to some of your other points, which are highly engaging, such as the neuroscience and its results from recent studies.
Overall, this post was a delight to read and of great interdisciplinary scope. I hope my small edits help, and I look forward to the final draft.
Cheers,
Shreya
Hi Shreya,
Thank you so much for your comments. Here are my responses:
1. This is a great point and I have incorporated this change into my final draft.
2. This is a good observation and I have included this into my final draft.
3. Thank you for this comment!
Overall, these were some great comments. Thank you for your help!
Rith
Hey Rith,
Fantastic blog post! You chose a very interesting topic and I thought this post was very well written.
I just have a few suggestions for you:
– The last sentence of the fourth paragraph could probably be rearranged to remove some of the commas and increase the flow of the sentence.
– In the figure two caption you mention that TMS positively stimulates neural pathways thousands of times. However, in the following paragraph you say that TMS stimulates the same neural pathways tens of thousands of times. To stay consistent, I would stick with a value of the same order of magnitude, as thousands are much different values than tens of thousands.
– This last suggestion is a bit nitpicky, but just to make the labels a bit bigger, perhaps consider enlarging your figures slightly more.
All in all, great work. Good luck in your editing stage!
Giancarlo
Hi Giancarlo,
These were all great comments. Thank you for providing them, I have implemented them all into my final draft.
Rith
Hi Rith,
Very interesting post and very well written. I have some suggestions that will hopefully make your post even better:
1. Consider splitting up the last sentence of the first paragraph; it seems kind of long.
2. For the second sentence of the second paragraph, consider taking out the phrase ‘despite its pervasiveness’. In the sentence prior, it’s already described that depression is highly prevalent.
3. For the second paragraph, last sentence, perhaps take out/revise the phrase relating to ‘significant gap’, as it’s not very clear what the gap is. I think the sentence is good as it is at the moment, but it could be made more clear.
4. Recent studies are mentioned in the last paragraph. I think it would be nice to add a sentence or two to elaborate more on the results of these studies. Also, you may need to reference the studies within the sentence.
5. It doesn’t seem like there is much space, but it would be interesting to write about the potential side effects of this treatment modality.
Overall, great post, and I look forward to reading your final draft.
Jonathan
Hi Jonathan,
These were all great comments. I have cited the “recent studies” sentence throughout my post, so their findings are interspersed all around this piece. I have mentioned the symptoms of TMS in the caption of Figure 1, but due to TMS being a relatively new technology, there have not been any significant symptoms detected from this technique yet. The process overall is painless and safe, just as I mentioned in the Figure 1 caption.
Thank you for your comments!
Rith
Hey Rith,
I think your blog post was very well written! I had a few suggestions that could help you improve your final draft:
1) In the first sentence of your first paragraph, you use major depressive disorder and depression synonymously. As of my knowledge, there are many different types of depression, which fall under that umbrella term. I would be careful with referring to major depressive disorder and depression as the same, and instead briefly discuss some of the types that can exist.
2) Figure 2 has a title (likely form the original source) that seems a bit misplaced. Since you are explain the context of the figure in your caption, I think this title can be cropped out.
3) There are some sentences in your blog that repeat or explain the same thing in different words. For example, your second paragraph explains that depression is persistent in a lot of the sentences, which could get repetitive to read. This can also help you with reducing word count and making the post more concise.
Overall, this post was extremely interesting and I loved the way you brought in integrated methods for therapy! I am excited to read the final product!
Best,
Sami
Hi Sami,
Thank you very much for these comments! Here are my responses.
1. This is a great point. To be more clear, I’ve used the phrase “clinical depression”. This is a very serious mental condition, but it is one specific form of depression. As you mentioned, there are different types of depression such as manic depression, psychotic depression, and postpartum depression, but I am specifically referring to major depressive disorder, a severe form of depression.
2. Great catch, I have implemented this into my final draft.
3. Thank you for this comment!
Rith
Hi Rith,
This is a very interesting and informative blog post! I just have a bit of feedback for you:
1. Some of your in-text citations are incorrect. For example, you have written “Basil, et al., 2005” when it should be “Basil et al., 2005”. You make this mistake a few times throughout the post, so just keep an eye out for that!
2. Saying “The physics principle governing the application of TMS is Faraday’s Law of Electromagnetic Induction, which states that every electric current is surrounded by a magnetic field and alternating currents produce fluctuating magnetic fields ” feels a bit awkward. I would suggest changing it to something more like “The application of TMS utilizes Faraday’s Law of Electromagnetic Induction, a principle which states that electric currents produce surrounding magnetic fields, and alternating currents produce fluctuating magnetic fields”.
3. In your second last paragraph, change “To explain this more clearly, consider this: while one positive thought will activate a positive neural pathway exactly one time, a conventional TMS treatment will activate that same positive pathway tens of thousands of times, wiring the brain to think in a more positive manner” to something more like “While a positive thought will activate a positive neural pathway exactly one time, a conventional TMS treatment will activate it tens of thousands of times. This will strengthen these neural pathways, wiring the brain to think in a more positive manner.” to improve clarity.
Great job overall! Happy editing,
Lily
Hi Lily,
Thank you for your comments, here are my responses.
1. I have checked the Anglia Ruskin citation guide, and I believe the format I have used is correct, maybe there was an update recently.
2. Thank you for your comment!
3. Thank you for your comment!
These are all great suggestions and I am so thankful for how pinpoint they all were. Thank you so much.
Rith
Hi Rith,
I thought your post was very well written and I thought you integrated multiple concepts very well.
I just have a few suggestions:
1. In the first sentence of your post, I would suggest specifying if the statistic is yearly. For example, you could write “…it affects more than 300 million people per year, spanning all races, ages…”
2. I believe your first sentence can be separated into two separate sentences as the one you have now seems to be quite long.
3. With in-text citations including ‘et al.’, I believe there is no comma after the first author’s name. I would suggest double-checking this with the citation style guidelines.
4. When introducing the limbic system in the fifth paragraph, I would suggest expanding on what this is. You could include different parts of the system or the general purpose of it.
Overall great post and good luck with your final version!
Cheers,
Keira
Hi Keira,
Thank you for your comments! Here are my responses.
1. This is not a yearly statistic, there are approximately 300 million people total around the world diagnosed with depression.
2. Thank you for the comment!
3. According to the ARU Harvard guide, a comma should be included in in-text citations that contain four or more authors.
4. This is an excellent point, thank you for the comment!
Rith