By Dr. David Woo - July 25, 2022
Depression is a mood disorder that affects one’s thought patterns, mood, and behavior. Common symptoms of depression include strong feelings of sadness and a loss of interest in activities that someone used to enjoy.(1)
There are different approaches to treating depression, and each form of depression therapy affects the brain in different ways. To understand the changes that occur in the brain during depression treatment, one must first understand how depression affects the brain.
What Is Happening in the Brain During Depression?
The brain functions by means of electrochemical activity, that is, through chemical and electrical properties. What this means is that brain cells, called neurons, interact with one another by using chemical messengers, known as neurotransmitters, and electrical pulses. When brain cells communicate with each other, they form neural networks or communication pathways that allow for communication between different regions of the brain.(2)
Studies have found symptoms of depression to be correlated with irregularities in neural networks known to be responsible for emotional response, pleasure-reward functions, and threat detection. These irregularities may include overactivity in the amygdala, a region of the brain that processes threats and fear-related behavior. The amygdala directly interacts with other regions of the brain, including the prefrontal cortex (PFC), the nucleus accumbens, and the hippocampus – a network that manages our response to emotions, among many other things. Dysfunction in these networks produces the symptoms of depression.(3,4,5)
It is possible to affect brain functions by altering neurochemical conditions and/or by electrical stimulation. This is the basis upon which physicians approach certain modern forms of depression therapy.
Antidepressants Chemically Stimulate Neurons
Antidepressant medication works to reduce symptoms of depression by altering the chemistry in the brain. These drugs specifically target neurotransmitters associated with depression, like serotonin, norepinephrine, and dopamine. Antidepressants are categorized into “classes” based on which neurotransmitter they affect.(6)
For example, selective serotonin reuptake inhibitors (SSRIs) are one kind of antidepressant that increase serotonin levels in the brain. Low levels of serotonin have been associated with depression. Serotonin is regularly released and reabsorbed by brain cells during brain activity. SSRIs block the reabsorption of serotonin to increase levels in the brain and make it more available to neurons. Increased levels of serotonin can improve neural connectivity and therefore reduce depressive symptoms.(7)
Antidepressants usually take a few weeks or more to start working, and patients may need to try a few different types of antidepressants before finding the right one for them. While antidepressants are effective at reducing symptoms of depression for many people, roughly 30% of people with depression are considered treatment-resistant, meaning they do not respond to medication.(8,9)
Transcranial Magnetic Stimulation (TMS) Stimulates Neurons Electrically
Studies show that transcranial magnetic stimulation (TMS) is a safe and effective treatment for depression, even for patients who don’t find relief from their symptoms with antidepressants.(10,11)
Unlike antidepressants, which chemically stimulate brain cells, TMS therapy uses magnetic pulses to electrically stimulate brain cells. Using an electromagnetic coil, TMS gently sends magnetic pulses to the brain through the scalp. These magnetic pulses create an electrical response that moderates activity in regions of the brain associated with depression.(10)
A recent study published in May 2022 sheds light on how TMS affects the brain to treat depression symptoms. During this study, researchers applied TMS therapy to patients while in an MRI machine to observe the effects of TMS on brain activity. Researchers saw, in real-time, that TMS pulses stimulating the prefrontal cortex also led to activation of other brain regions associated with depression. After 4 weeks of continued TMS treatment, researchers were able to directly correlate patients having fewer symptoms of depression with activated regions of the brain from TMS therapy.(4)
Learn More about Depression Treatment
If you are suffering from symptoms of depression, it is important that you seek help. Delaying seeking help or a delay in treatment could lead to worsening depression. To book an appointment at Madison Ave TMS & Psychiatry, contact us online or call (212) 731-2033.
1. Depression (major depressive disorder). MayoClinic. Published July 29, 2021.
https://www.mayoclinic.org/es-es/diseases-conditions/depression/symptoms-causes/syc-20356007. Accessed June 22, 2022.
2. Brain Basics: The Life and Death of a Neuron. National Institute of Neurological Disorders and Stroke. Updated April 1, 2022. https://www.ninds.nih.gov/health-information/patient-caregiver-education/brain-basics-life-and-death-neuron. Accessed June 22, 2022.
3. Phillips ML, Chase HW, Sheline YI, et al.: Identifying predictors, moderators, and mediators of antidepressant response in major depressive disorder: neuroimaging approaches. Am J Psychiatry. 2015;172:124–138. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4464814/. Accessed June 22, 2022.
4. Ge R, Humaira A, Gregory E, et al. Predictive Value of Acute Neuroplastic Response to rTMS in Treatment Outcome in Depression: A Concurrent TMS-fMRI Trial [published online ahead of print, 2022 May 18]. Am J Psychiatry. 2022;appiajp21050541. https://pubmed.ncbi.nlm.nih.gov/35582784/. Accessed June 22, 2022.
5. Neuroscience of depression and treatment. New Frontiers Psychiatry & TMS. Published November 8, 2021. https://www.newfrontierspsychiatry.com/neuroscience-of-depression-and-treatment/. Accessed June 22, 2022.
6. Antidepressants: Selecting One That’s Right for You. MayoClinic. Published December 31, 2019. https://www.mayoclinic.org/diseases-conditions/depression/in-depth/antidepressants/art-20046273. Accessed June 22, 2022.
7. Selective Serotonin Reuptake Inhibitors (SSRIs). MayoClinic. September 17, 2019. https://www.mayoclinic.org/diseases-conditions/depression/in-depth/ssris/art-20044825. Accessed June 22, 2022.
8. Depression: How Effective Are Antidepressants? National Library of Medicine. Updated June 18, 2020. https://www.ncbi.nlm.nih.gov/books/NBK361016/. Accessed June 22, 2022.
9. Ionescu DF, Rosenbaum JF, Alpert JE. Pharmacological approaches to the challenge of treatment-resistant depression. Dialogues Clin Neurosci. 2015;17(2):111-126. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4518696/. Accessed June 22, 2022.
10. Transcranial Magnetic Stimulation. MayoClinic. Published November 27, 2018. https://www.mayoclinic.org/tests-procedures/transcranial-magnetic-stimulation/about/pac-20384625. Accessed June 22, 2022.11. Somani A, Kar SK. Efficacy of repetitive transcranial magnetic stimulation in treatment-resistant depression: the evidence thus far. Gen Psychiatr. 2019;32(4):e100074. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6738665/. Accessed June 22, 2022.