By Dr. David Woo - October 16, 2023
Neurostimulation—a type of therapy that uses electricity to stimulate brain activity—has gained prominence in psychiatry for its potential to treat a range of mental health conditions. Transcranial Magnetic Stimulation (TMS) and Transcranial Direct Current Stimulation (tDCS) are two kinds of non-invasive neurostimulation techniques you may see offered as a treatment for depression, obsessive-compulsive disorder (OCD), or other kinds of mental illness. TMS utilizes a magnetic field to stimulate specific brain regions, while tDCS involves the application of low-level electrical currents directly to the scalp.
Both kinds of neuromodulation are based on our knowledge of how the brain works—that irregularities in the brain’s electrochemical activity can cause the symptoms of mental illness—for example, the deficiency in the production of serotonin in the prefrontal cortex can cause symptoms of depression. By using electricity to stimulate the brain’s natural electrochemical activity, these therapies modulate or “fix”, these irregularities and alleviate a patient’s symptoms.
Although TMS and tDCS may sound similar, there are many differences that patients should be aware of before trying one of these therapies. To help you make an informed decision, we’ll compare these two modern neurostimulation techniques, outlining their differences in mechanisms, applications, benefits, and potential drawbacks.
What Is Transcranial Magnetic Stimulation (TMS)?
How TMS works
TMS, first introduced in the mid-1980s, uses rapidly changing magnetic fields to induce small electrical currents in targeted brain areas. TMS is applied by a helmet-like device, known as a coil, that generates tiny, barely perceptible magnetic pulses that penetrate the skull and stimulate the neurons.
Common Uses and Indications
TMS is primarily used in the treatment of major depressive disorder (MDD) and has received FDA approval due to the effectiveness of TMS for depression, as well as for OCD. It is also used to manage other mental health conditions such as anxiety and post-traumatic stress disorder (PTSD).
Benefits and Potential Side Effects
TMS is a non-invasive procedure with only minimal reported side effects in a small minority of patients. However, some individuals may experience mild discomfort or headaches during or after the procedure. Although extremely rare, one known side effect is seizure. TMS seizure statistics show that a tiny minority (less than 1%) of patients may experience seizures, which is the same risk that comes with taking antidepressant or anti-anxiety medications.
What Is Transcranial Direct Current Stimulation (tDCS)?
How tDCS Works
tDCS, with its roots dating back to the early 19th century, involves the application of a low, direct electric current to the scalp using electrodes. tDCS works by altering the resting membrane potential of neurons and can enhance or suppress brain activity depending on the polarity of the stimulation.
Common Uses and Indications
Unlike TMS, tDCS is not FDA-approved for any specific medical use, however, it has been explored as a potential therapy for various mental health conditions, including depression, chronic pain, and cognitive enhancement (to boost memory and concentration). It is also used in research settings to investigate brain functions. Because tDCS devices are simpler and cheaper to make than TMS coils, they are often sold and marketed for home use, making them more accessible than TMS for many patients.
Benefits and Potential Side Effects
tDCS is relatively safe and well-tolerated. Side effects are generally mild and can include tingling sensations, itching, or mild headaches. However, it is important to note that tDCS is still largely unregulated and uncertified, and the various tDCS devices sold for home use or administered by non-physicians cannot guarantee the safety controls one would find in a clinical setting.
TMS VS tDCS Comparison Table
Let’s compare TMS and tDCS based on key criteria:
|Mechanism||Tiny magnetic fields to targeted brain area||Direct electrical current to scalp|
|Application||Used to treat MDD, OCD, anxiety, ADHD, PTSD||Used for research and as a potential therapy for mental health disorders|
|Duration of Treatment||Daily sessions for several weeks||Often shorter, daily, or as needed|
|Side Effects||Headache, scalpdiscomfort, rare seizures (less than 1%)||Mild side effects, e.g., tingling, rare seizures. However, devices are unregulated/uncertified and may carry risk|
|Cost||Moderate to high (average $7000 – $8000 for complete treatment). May be covered be health insurance.||Relatively low ($50-$500 for a personal device). Not covered by insurance.|
|Efficacy||Proven for some conditions, FDA-approved for MDD and OCD||Varied, more research needed|
|Contraindications||Certain medical and metal implants||Certain medical and metal implants, migraines, recent head trauma|
TMS VS tDCS: Clinical Studies and Evidence
There are only a few clinical studies that have made a head-to-head comparison of TMS and tDCS. However, one recent paper did compare the results of similar studies and found that both therapies were generally effective and well-tolerated and could benefit patients with MDD when applied in different ways (1).
A pilot study on tDCS for home use, with remote monitoring by physicians has shown promising results, with patients achieving a reduction in depression symptoms (2). However, further research using control groups and larger samples is required.
TMS, on the other hand, has a well-documented success rate of around 75% for treating MDD, with similar results for OCD (3,4) While TMS has received FDA approval for these conditions, tDCS is still in the investigational stage for many indications. Although research continues to evolve, the balance of evidence favors TMS as a safe and effective neurostimulation therapy.
While TMS and tDCS are based on the same scientific principles, only TMS is FDA-approved and regulated for mental health treatments. As such, TMS is more widely used by doctors and recommended for individuals with treatment-resistant depression and other mood disorders.
As always, it is crucial to consult with healthcare professionals to determine the most suitable approach for your needs when it comes to any mental health condition. Madison Avenue TMS & Psychiatry offers talk therapy and TMS for treating depression, anxiety, and other mental health disorders. Contact us online or call (212) 731-2033 if you have any questions or to make an appointment.
- Hejzlar, M., Novak, T., & Bares, M. Neurostimulation Methods in the Treatment of Depression: A Comparison of rTMS, tDCS, and Venlafaxine Using a Pooled Analysis of Two Studies. Neuropsychiatric Disease and Treatment. 2021;17, 1713-1722. Link. Accessed September 22, 2023.
- Alonzo A, Fong J, Ball N, Martin D, Chand N, Loo C. Pilot trial of home-administered transcranial direct current stimulation for the treatment of depression. J Affect Disord. 2019;252:475–483. Link. Accessed September 22, 2023.
- 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. July 2012;29(7):587-96. Link. Accessed September 17, 2023.
- Roth et. al. Real-world efficacy of deep TMS for obsessive-compulsive disorder: Post-marketing data collected from twenty-two clinical sites. Journal of Psychiatric Research. 2021;137:667-672. Link. Accessed May 3, 2022.