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How Mental Illness Affects the Brain

It’s normal to feel sad, anxious, or confused at various moments throughout life. These various emotions are all byproducts of the brain responding to specific stimuli and situations. One in five U.S. adults experienced a mental illness in 20204

Feeling negative emotions too much or too little could be the brain’s reaction to a developing or present mental illness. Mental illness refers to thinking, feeling, or acting in a way that causes distress and difficulty functioning in everyday life2.

As with many diseases, mental illness is severe in some cases and mild in others. Mental illness does not always cause outward symptoms, especially if the illness is mild. Explicit symptoms such as confusion, agitation, or withdrawal can be seen in more extreme cases.

Many mental illnesses include depression, bipolar disorder, attention deficit hyperactivity disorder (ADHD), generalized anxiety disorder, and obsessive-compulsive disorder. Each illness alters thoughts, feelings, behaviors, and the brain in distinct ways.

Mental Illness and Brain Chemistry

The term mental illness indicates a problem with the mind. Mental illness can be seen in an abstract sense and physically. As scientists continue to investigate mental illnesses and their causes, more can be learned about how the biological processes that make the brain work are changed by mental illness.

Brain Function Explained

The brain is an incredibly complex organ that makes up only 2 percent of the human body’s weight. However, the brain consumes 20 percent of the oxygen we breathe and 20 percent of our energy 2. This controls virtually everything humans experience, including movement, sensing the environment, regulating involuntary body processes such as breathing, and controlling emotions.

Hundreds of thousands of chemical reactions occur every second in the brain. Those reactions underlie the thoughts, actions, and behaviors we respond to environmental stimuli. In short, the brain dictates the internal processes and behaviors that allow survival.

Brain and Mental Health

Researchers at Stanford University School of Medicine analyzed brain images of nearly 16,000 people and discovered a common pattern across the spectrum of psychiatric disorders 1. These areas are the dorsal anterior cingulate cortex, the right insula, and the left insula. Many psychiatric disorders share a common structural root, making applying therapies for one disorder to another easier.

There are also changes in chemicals found in receptors in the brain. Depression is believed to be caused by the lack of the neurotransmitter serotonin found in various receptors. Dopamine can be an important neurotransmitter in treating schizophrenia1.

The key takeaway is that various mental illnesses physically and chemically impact the human brain. Mental health disorders that can affect the brain include attention deficit hyperactivity disorder (ADHD),  generalized anxiety disorder (GAD), schizophrenia, bipolar disorder, obsessive-compulsive disorder (OCD), and depression.

Depression and the Brain

Depression is more than just feeling down; it may physically change the brain. Depression can affect thinking, feelings, and behaviors. Experts aren’t sure what causes these changes but think genetics, stress, and inflammation might play a role.

It’s important to get help for depression. That’s because repeat episodes seem to damage the brain more and more over time. Early treatment might help avoid or ease changes in the brain.

Brain Size

There’s some debate about which areas are affected and how much. There’s growing evidence that several brain parts shrink in people with depression5. Specifically, these areas lose gray matter volume (GMV), tissue with many brain cells. GMV loss seems higher in regular or ongoing depression with serious symptoms.

Studies show depression can lower GMV in the hippocampus and the prefrontal cortex areas. The hippocampus is the part of the brain important for learning and memory. It connects to other parts of the brain that control emotion and is responsive to stress hormones. That makes it more vulnerable to depression.

The prefrontal cortex is an area in the brain responsible for controlling higher-level thinking and planning. This cortex comprises three regions, all of which evidence states can become smaller with depression. These are the thalamus, the caudate nucleus, and the insula.

Results are mixed on how depression affects the amygdala, the brain’s fear center. Some studies show it gets smaller. Others found that stress and depression might boost its GMV. The more severe the depression, the higher the GMV.

When these areas don’t work the right way or become smaller, you may see issues with5:

  • Memory problems
  • Trouble thinking clearly
  • Guilt or hopelessness
  • Lack of motivation
  • Sleep or appetite problems
  • Increased anxiety

Treatment Options

Medications and psychotherapy can be effective treatments for depression6. A primary care doctor or psychiatrist can prescribe medications to relieve symptoms. However, depression treatment can also benefit from seeing a psychiatrist, psychologist, or other mental health professionals.

Antidepressants such as selective serotonin reuptake inhibitors (SSRIs), serotonin-norepinephrine reuptake inhibitors (SNRIs), and monoamine oxidase inhibitors (MAOIs) can be effective treatments for depression6. These medications each have different ways of battling depression and come with varying side effects, lesser and severe. Be sure to discuss possible major side effects with a doctor or pharmacist.

Transcranial Magnetic Stimulation (TMS) for depression is administered through an electromagnetic coil on the top of the head 15. Unlike medication, TMS is non-invasive and comes with little to no side effects. To treat depression, TMS targets areas of the brain to stimulate the dorsolateral prefrontal cortex that helps to regulate mood.

Bipolar Disorder and the Brain

Bipolar disorder is a mental health condition that affects moods, which can swing from one extreme to another8. More than 2 million Americans suffer from bipolar disorder, commonly known as manic depression. To date, there are no physiological markers used to diagnose the disease. Instead, it is identified by behavioral symptoms, including frequent mood swings between high-energy mania and severe depression.

Bipolar disorder is widely believed to result from chemical imbalances in the brain. The chemicals responsible for controlling the brain’s functions are called “neurotransmitters, ” including noradrenaline, serotonin, and dopamine. Some evidence suggests that having an imbalance in the levels of one or more neurotransmitters may increase the risk of developing bipolar disorder symptoms.

Researchers at the San Francisco VA Medical Center indicate that people with bipolar disorder may suffer progressive brain damage9. This study compared the brain scans of 15 non-symptomatic males with bipolar disorder against 20 of those without the disorder.

Low levels of N-acetyl aspartate (NAA) were found in people with bipolar disorder brains. NAA is an amino acid in the hippocampus that plays a large part in the brain’s complex neural circuits regulating emotion and memory. Those with bipolar disorder the longest showed the lowest levels of this amino acid.


Mood swings and other symptoms of bipolar disorder can be controlled with proper treatment10. Because bipolar disorder is a chronic illness, treatment can be ongoing. Symptoms of bipolar disorder can get worse without proper treatment and diagnosis.

Methods to treat bipolar disorder include10:

1. Cognitive Behavioral Therapy: This helps change the negative thinking and behavior associated with depression. The goal of this therapy is to recognize negative thoughts and to teach coping strategies.

2. Psychotherapy: focuses on self-care and stress regulation. It also works to help a person recognize patterns of symptoms and manage stress.

3. Medications: When prescribed by a doctor, different types of bipolar disorder may respond better to a particular type of medication. The side effects can vary between medications, and it may take time to discover the best medicine. Mood stabilizers, antidepressants, anti-psychotics, and anti-anxiety medications can be prescribed as a treatment for bipolar disorder symptoms.

4. Transcranial Magnetic Stimulation (TMS): depressive episodes can be treated with TMS targeted at the left frontal cortex, while manic episodes are targeted to the right prefrontal cortical regions13

ADHD and the Brain

Attention-Deficit/Hyperactivity Disorder (ADHD) is characterized by inattention, hyperactivity, and impulsivity. ADHD is one of the most frequently diagnosed neurodevelopmental disorders, with a prevalence rate of approximately 5% in children and 2.5% in adults3.

Estimates suggest that 65% of children with ADHD continue to have problems in adulthood. ADHD is well-characterized at the behavioral level in children. However, more is to be researched about the association between brain structure and ADHD diagnosis.

ADHD brains have low levels of a neurotransmitter called norepinephrine. Norepinephrine is linked with dopamine, the neurotransmitter responsible for controlling the brain’s reward and pleasure center3.

The ADHD brain has impaired activity in four functional regions of the brain:

  • Frontal cortex: controls high-level functions such as attention, executive function, and organization
  • Limbic system: located deeper within the brain where it regulates emotions and attention
  • Basal ganglia: a deficiency can cause inter-brain communication and information to “short-circuit,” causing inattention or impulsivity
  • Reticular activating system: key relay system where a deficiency can cause inattention, impulsivity, or hyperactivity

Treatment Options

Types of treatment for ADHD vary, with researchers supporting various methods for dealing with the disorder. These methods include:

  • Cognitive Behavioral Therapy: Its main goals are to help teach or strengthen positive behaviors and eliminate unwanted problem behaviors.
  • Medications: Stimulants are the best-known and widely used ADHD medications. Non-stimulants, approved for treatment in 2003, can also help with ADHD.
  • Transcranial Magnetic Stimulation (TMS): non-invasive and medication-free treatment to target the right prefrontal cortex commonly associated with ADHD with electromagnetic waves 11

Anxiety and the Brain

Everyone experiences fear and anxiety at some point in their lives. Fear is an immediate response to a specific threatening stimulus. Anxiety is a less intense feeling but a more sustained response to anxiety-inducing sources that may be known.

The sensation of anxiety can be overwhelming, and it can start to interfere with daily life. Anxiety can become a problem when these brain areas function inappropriately, setting off a stream of inappropriate or irrational behaviors. Long-lasting anxiety like this may be diagnosed as an anxiety disorder4. Anxiety disorders, like panic disorder or social anxiety disorder, may require treatment to allow for a normal and happy life.

Researchers see anxiety results from constant chatter between several different brain regions, described as a fear network. No one brain region drives anxiety on its own but instead involves interactions between many brain regions.

One potential explanation for this is splitting the brain into a cognitive and emotional brain. According to this theory, anxiety is felt when signals from the emotional brain overpower the cognitive brain. The frontal lobe, where all of our sensations and thoughts come together as one unified experience, is the cognitive brain. The amygdala, located deep inside the brain, is part of the emotional brain.

Treatment Options

Anxiety treatment can include behavioral therapy, medication, or alternative methods. Behavioral therapy can include gradual exposure to triggers that set off anxiety. Over time, repeated exposures can lead to overcoming anxiety because a realization can occur that the situations do not cause actual harm.

Medications for anxiety can include benzodiazepines and antidepressants. Benzodiazepine medications can come with severe side effects and the potential for addiction. Depending on the medication, side effects can include drowsiness, dizziness, and confusion.

Transcranial magnetic stimulation (TMS) can be an alternative treatment for anxiety disorders. TMS for anxiety targets the right dorsolateral prefrontal cortex in the brain12. TMS produces little to no side effects and can help reduce anxiety symptoms.

OCD and the Brain

Obsessive-compulsive disorder (OCD) is associated with a cycle of obsessions and compulsions and affects people of all ages and walks of life7. An obsession is an intrusive thought, image, or urge that triggers intensely distressing feelings. Compulsions are behaviors that are engaged in to get rid of obsessions and decrease distress.

These thoughts, images, or impulses that occur repeatedly can feel out of control. Often OCD thoughts or behaviors can be disturbing, unwanted, and lack common sense.

Although the exact cause of OCD is still unknown, research shows that genetics and brain differences may play a role. Research suggests that OCD involves problems in communication between the front part of the brain and deeper structures of the brain.

OCD was one of the first psychiatric disorders in which brain scans showed evidence of abnormal brain activity in specific regions. Positron emission tomography (PET) scans are imaging tests that can help reveal the metabolic or biochemical function of tissues and organs. PET imaging measures brain activity, brain metabolism, and blood flow. All of which showed differences in the scans of brains with OCD and without.

Treatment for OCD

Obsessive-compulsive disorder treatment can include medication, psychotherapy, and FDA-approved transcranial magnetic stimulation7. Cognitive behavioral therapy (CBT) can help reduce the symptoms and severity of OCD. Specifically, CBT can help with the compulsive behaviors related to OCD by exposure to situations that trigger behaviors.

Medication for OCD typically includes serotonin reuptake inhibitors (SRIs) and selective serotonin reuptake inhibitors (SSRIs). Medications typically take up to three months to become effective and can have serious side effects.

TMS for OCD is now FDA-approved and involves stimulating parts of the brain associated with compulsivity and obsessive thoughts. TMS provides an alternative medicine treatment with little to no side effects.

Your Brain Can Be Helped

The brain’s reaction to various mental health illnesses such as depression, anxiety, ADHD, and more have been well studied and documented. New powerful therapies such as transcranial magnetic stimulation (TMS) have been emerging and are backed by research and trials. 

The TMS technique is non-invasive and stimulates the human brain without causing significant discomfort. If you or a loved one have been struggling with mental health disorders, please give Brain Therapy TMS a call. Our team can answer any questions you may have and give you a better understanding of our program.


  1. Goldman, B. (2015, February 4). Different mental disorders linked to brain-matter loss, study finds. Retrieved April 13th, 2022 from
  2. National Library of Medicine (2007). Information about Mental Illness and the Brain. Retrieved April 13th, 2022 from
  3. Gehricke, J.G., Tatos, E.(2017, April 13). The brain anatomy of attention-deficit/hyperactivity disorder in young adults – a magnetic resonance imaging study. Retrieved April 13th, 2022 from
  4. Gadye, L. (2018, June 29). What Part of the Brain Deals With Anxiety? What Can Brains Affected by Anxiety Tell us? Retrieved April 13th, 2022 from
  5. Trifu, S.C., Trifu, A.C. (2020, December 8). Brain changes in depression. Retrieved April 13th, 2022 from
  6. Mayo Clinic (2018, February 3). Depression (major depressive disorder). Retrieved April 13th, 2022 from
  7. NIMH. (2019, October). Obsessive-compulsive disorder. National Institute of Mental Health. Retrieved April 18, 2022, from
  8. National Health Society of UK (2019, March 14). Causes – Bipolar disorder. Retrieved April 13th, 2022 from
  9. Rey, C.M. (2003, May 6). The study suggests bipolar disorder may cause progressive brain damage. Retrieved April 13th, 2022 from
  10. National Alliance on Mental Illness. Bipolar Disorder. Retrieved April 13th, 2022 from
  11. Alyagon, U., Shahar, H., Hadar, A., Barnea-Ygael, N., Lazarovits, A., Shalev, H., & Zangen, A. (2020, February 6). Alleviation of ADHD symptoms by non-invasive right prefrontal stimulation is correlated with EEG activity. NeuroImage. Clinical. Retrieved April 18, 2022, from
  12. Cirillo, P., Gold, A. K., Nardi, A. E., Ornelas, A. C., Nierenberg, A. A., Camprodon, J., & Kinrys, G. (2019, May 7). Transcranial magnetic stimulation in anxiety and trauma-related disorders: A systematic review and meta-analysis. Brain and behavior. Retrieved April 18, 2022, from
  13. Gold, A. K., Ornelas, A. C., Cirillo, P., Caldieraro, M. A., Nardi, A. E., Nierenberg, A. A., & Kinrys, G. (2019, September 30). Clinical applications of transcranial magnetic stimulation in bipolar disorder. Brain and behavior. Retrieved April 18, 2022, from
  14. NAMI. (2021). Mental health by the numbers. National Alliance on Mental Illness. Retrieved April 18, 2022, from
  15. Rizvi, S., & Khan, A. M. (2019, May 23). Use of transcranial magnetic stimulation for depression. Cureus. Retrieved April 18, 2022, from



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