The incidence of mood disorders is more prevalent than it has ever been, and this number continues to rise. An estimated 21.4% of adults in the United States will experience a mood disorder sometime in their lives, with the highest prevalence stemming from college-aged individuals. One of the most common mood disorders is major depressive disorder or MDD. MDD significantly affects the social, personal, and economic well-being of those who experience it. Key symptoms of MDD include anhedonia (loss of interest in previously enjoyable activities), persistent low mood, sleep impairment, weight fluctuations, and pervasive negative thoughts that can lead to feelings of guilt and, in some cases, suicidal ideations. Those experiencing MDD not only deal with a decreased quality of life but also have a greater risk of comorbidities, including anxiety disorders, substance-use disorders, eating disorders, as well as chronic medical conditions such as chronic pain, diabetes, cardiovascular diseases, etc. In recent years, there has been a surge of drugs to treat MDD. Most commonly, selective serotonin reuptake inhibitors (SSRI) and serotonin-norepinephrine reuptake inhibitors (SNRI). However, as of 2016, about 30% of patients presented drug refractoriness, meaning their condition was unresponsive to treatment. The high prevalence of MDD, along with the potential for drug refractoriness, has created a need for a novel treatment method. One of these developing treatment methods is transcranial magnetic stimulation.
Transcranial magnetic stimulation (TMS) is a non-invasive treatment method that utilizes magnetic pulses to stimulate target regions of the brain. It is FDA-approved to treat major depression, OCD, and even instances of smoking addiction. However, it is not often prescribed due to barriers such as cost, availability, and stigma. TMS involves placing a wire on the scalp and passing a strong current through it to produce a magnetic field that can penetrate the cortex. As a result of this changing magnetic field, the brain generates a current that passes through neurons, causing action potentials that lead to excitatory or inhibitory post-synaptic potentials.
In the case of MDD, scientists have identified specific regions of the brain that are underactive or overactive. One important site is the dorsolateral prefrontal cortex (DLPFC). In MDD, the DLPFC has right-side hyperfunction and left-side hypofunction. TMS works by stimulating the hypoactive regions of the DLPFC, which has been proven to successfully improve symptoms of depression.
So, how does the process of getting TMS treatment work? Like many medical treatments, the process starts with getting a prescription from a psychiatrist. Once prescribed, an intake appointment will be made to take head measurements, determine the correct device positioning, and measure the motor threshold or minimum amount of stimulation to achieve a motor response. After the setup, treatments are conducted five days a week, lasting 20 minutes for the first 4-6 weeks and then decreasing in frequency as treatment continues. According to a source from PsychCentral, who herself received TMS treatment, the process feels like getting repeatedly and vigorously tapped on the head. TMS has various possible side effects, including dizziness, tingling or twitching of the face, headaches, and scalp discomfort.
While TMS is still in the beginning stages of development, its results are promising for those who fail to achieve relief from commonly used drugs and therapies. Effective treatment for mood disorders is not only essential for the personal well-being of individuals but also has a significant impact on the health of our communities, making this a prominent issue for the future of our society.
Sources:
Allan, Charlotte L., et al. “Transcranial magnetic stimulation in the management of mood disorders.” Neuropsychobiology, vol. 64, no. 3, 2011, pp. 163–169, https://doi.org/10.1159/000328951.
“Any Mood Disorder.” National Institute of Mental Health, U.S. Department of Health and Human Services, http://www.nimh.nih.gov/health/statistics/any-mood-disorder. Accessed 16 Nov. 2024.
Brunoni, André, and Colleen Loo. “Mood disorders.” Transcranial Direct Current Stimulation in Neuropsychiatric Disorders, 2016, pp. 233–244, https://doi.org/10.1007/978-3-319-33967-2_13.
Elmer, Jamie. “TMS: What It Felt like for Me.” Psych Central, Psych Central, 29 Mar. 2022, psychcentral.com/health/my-experience-with-tms#What-getting-TMS-was-like-for-me.
“Major Depression.” National Institute of Mental Health, U.S. Department of Health and Human Services, http://www.nimh.nih.gov/health/statistics/major-depression. Accessed 16 Nov. 2024.
“Transcranial Magnetic Stimulation.” Mayo Clinic, Mayo Foundation for Medical Education and Research, 7 Apr. 2023, www.mayoclinic.org/tests-procedures/transcranial-magnetic-stimulation/about/pac-20384625.
King Lab at Creighton University 