By Dr. David Woo - March 5, 2020
Transcranial magnetic stimulation (TMS) is proven to relieve symptoms of depression in patients who don’t find symptom relief with other treatments like antidepressants and therapy. (1,2) Most patients go through TMS with zero to mild side effects. But some patients may experience what is commonly called a “dip” about halfway through treatment. A dip is a temporary worsening of symptoms and can feel frustrating for patients who had expected to only feel positive results from treatment. Why does this dip happen? And how common is it?
To gain a better understanding of the TMS dip, let’s first take a look at how TMS works.
How Does TMS Work to Relieve Symptoms of Depression?
TMS uses magnetic waves to stimulate the electrical activity of neurons (nerve cells) in the brain that are either underactive or inactive. TMS is administered using a special coil that is carefully positioned over a specific part of the head. The position of the coil ensures that the magnetic pulses target a specific region of the brain known to be associated with depression (the dorsolateral prefrontal cortex, or DLPFC).
When these neurons are electrically stimulated, they begin to “reactivate” and release neurotransmitters (special chemicals that allow the brain’s neurons to communicate with each other). In other words, TMS “resets” neurons, and allows them to change the way they connect and communicate with each other, therefore forming new neural pathways. (3,4,5)
When an individual is suffering from depression, their brain is accustomed to functioning in certain patterns using specific neural pathways—similar to a habit. TMS disrupts these neural “habits” associated with depression, and allows the brain to form new patterns. New neural pathways allow the brain to start using new communication patterns that positively affect the patient’s thinking and behavior.
Why Does the TMS “Dip” Occur?
As explained above, TMS electrically stimulates neurons in the brain. This stimulation causes a temporary disruption of the brain’s normal pattern of activity (its “habits”). This disruption can affect patients in one of two ways: as a) increased alertness and/or energy, or b) as a worsening of depression symptoms.
This disruption is only temporary, and with time, the brain forms new neural pathways. When the brain forms new neural pathways, patients start to experience the real benefits of TMS. The new neural pathways in the DLPFC (the part of the brain that is targeted during TMS sessions) also form new connections with other parts of the brain. These new connections change the way that different parts of the brain communicate with each other. An entirely new network of communication is created, with new neural pathways and patterns of functioning. (4,5)
The construction of new pathways takes time, usually weeks. This is because, to create these new connections, the brain must produce and use a lot of energy. The brain uses certain substances, like fatty acids, amino acids, and phospholipids to generate energy to form new neural pathways.
How Common is the TMS Dip?
In our clinic, roughly 20% of patients experience a temporary exacerbation of symptoms, which often occurs in the 2nd or 3rd week of treatment. During a dip, patients may experience worsening depression or anxiety.
TMS isn’t the only treatment that sometimes comes with a “dip.” Patients taking antidepressant medications may also experience a dip: at first, their symptoms may seem to get worse and the side effects of the medication may not seem worth the benefits. But for most patients, over time, the brain adjusts to the medication and patients begin to see a relief of symptoms. (But many patients will never see a relief of symptoms with antidepressants, and for those patients, TMS is an excellent alternative.)
What Should You Do if You Experience a Dip During TMS Treatment?
If you’re currently undergoing TMS therapy and are experiencing a dip, talk to your doctor. It’s very important to continue with treatment, even if a dip occurs. Your doctor can talk to you about how to manage your symptoms during the dip, and may recommend that you integrate wellness practices into your depression treatment.
Learn more about how TMS work and the benefits of this therapy.
1. Carpenter LL, Janicak PG, Aaronson ST, et al. Transcranial magnetic stimulation (TMS) for major depression: A multisite, naturalistic, observational study of acute treatment outcomes in clinical practice. Depression and Anxiety. 2012;29(7):587-96. https://www.ncbi.nlm.nih.gov/pubmed/22689344. Accessed February 13, 2020.
2. Dunner DL, Aaronson ST, Sackeim HA, et al. A multisite, naturalistic, observational study of transcranial magnetic stimulation for patients with pharmacoresistant major depressive disorder: Durability of benefit over a 1-year follow-up period. The Journal of Clinical Psychiatry. 2014;75(12):1394-401. https://www.psychiatrist.com/jcp/article/Pages/2014/v75n12/v75n1207.aspx. Accessed February 13, 2020.
3. Neurostar mechanism of action. YouTube: Neurostar Advanced Therapy https://www.youtube.com/watch?v=r4WISNwv3nc&t=. Published on Nov 29, 2016. Accessed February 13, 2020.
4. Kozyrev V, Staadt R, Eysel UT, and Jancke D. TMS-induced neuronal plasticity enables targeted remodeling of visual cortical maps. June 2018;115(25):6476-6481. https://www.pnas.org/content/115/25/6476. Accessed February 13, 2020.
5. Ruhr-University Bochum. What effect does transcranial magnetic stimulation have on the brain? Published June 5, 2018. https://www.sciencedaily.com/releases/2018/06/180605103511.htm. Accessed February 13, 2020.