How Does Depression Affect the Brain?

How Does Depression Affect the Brain?

Recent brain imaging studies have shown that the brains of people who experience depression show signs of shrinkage, inflammation, and malfunctions in the way neurons fire and in their pathways.^{2, 3} It’s important to understand that research on the neurobiology of depression and other mental illnesses is still in the early phases, and there is a lot scientists are still trying to understand.

For example, it’s unclear whether some of the brain abnormalities seen in depression are caused by depression or by something else. Even among scientists who believe depression alters the brain, there are disagreements about the exact mechanisms that lead to these changes.^{1, 2, 3}

Here are a few ways that depression can affect the brain:

Brain Shrinkage in Depression

A number of studies show reduced gray matter volume in the brains of depressed individuals, leading many scientists to hypothesize that depression can cause brain shrinkage.^{1, 2, 3} Most researchers believe that people with severe forms of depression that go untreated for several years are at higher risk for brain shrinkage, suggesting that the effects of depression are gradual and happen over time.

Brain shrinkage appears to affect the gray matter volume only in specific regions of the brain, including:^{1, 2, 3}

• Hippocampus: A part of the brain involved in learning, emotional regulation, and memory development and recall. Shrinkage in this region may help explain depression-induced brain fog, memory problems, poor concentration, and negative thought patterns in people with depression.
• Prefrontal cortex: The area of the brain that is linked to higher-level critical thinking, problem-solving, impulse control, planning, judgment, and decision-making. Shrinkage in this region may help explain mood problems, cognitive impairments, and impulsivity experienced by some people with depression.
• Thalamus: The region of the brain that helps with sensory processing, motor signals, and providing energy, motivation, and drive. Shrinkage in this region may help explain the sluggishness, lethargy, loss of energy, decreased motivation, and sleep problems associated with depression.

Increased Amygdala Size in Depression

While it hasn’t been a consistent finding (a few studies show shrinkage in the amygdala), there have been studies showing increases in amygdala size linked to depression.⁸ The amygdala is the region of the brain involved in detecting danger, activating the fight or flight response, and conditioning behavioral responses.¹ Growth in this region of the brain is believed to lead to increased stress and anxiety, more impulsivity, and a higher risk of mood disorders like depression.⁸

Brain Inflammation in Depression

A number of studies have also found evidence of increased inflammation in people who have depression, and some researchers have even postulated that depression may be an inflammatory disease. High levels of inflammatory markers have been found in people who experience depression, with specific markers that indicate inflammation in the brain. While it isn’t yet known whether inflammation triggers depression or vice versa, a surprising number of studies have confirmed a link between depression and inflammation in the brain.^{2, 3, 8, 9, 10}

When the brain becomes inflamed, it can trigger a number of effects that may help to explain some of the symptoms of depression. For example, an inflamed brain processes information more slowly because of the way inflammation interrupts the firing of neurons. This might explain why people who experience depression often experience brain fog. Brain inflammation can also interfere with the brain’s ability to produce mood-boosting chemicals like dopamine and serotonin, which can lead to a depressed mood.^{9, 10}

Inflammation can prevent the formation of new brain cells as well as accelerate the decline of existing ones, leading to premature aging and cognitive decline.³ Because of how much energy your immune system requires to fight inflammation, it can force your body to conserve energy through the development of ‘sickness behaviors.’² Sickness behaviors are involuntary changes in mood and behavior that are meant to reduce the amount of energy being used.^{9, 10}

Neural Abnormalities in Depression

Brain cells communicate through chemical signals called neurotransmitters, so neural connectivity issues can lead to a wide range of impairments. Because of a pattern of abnormal fMRI and PET scan results seen in people who experience depression, some researchers believe that faulty neural networks in the brain cause depression. Most who support this theory believe that a combination of genes and environmental stress can trigger faulty wiring.^{1, 3, 4, 8}

According to this theory of how depression affects the brain, it’s suggested that high levels of stress hormones like cortisol can be neurotoxic, impairing the connectivity and communication between brain cells. It’s also believed that over time, this can slow the generation of new nerve cells, leading to some of the characteristic mood problems and cognitive deficits, such as pseudodementia, seen in depression.^{1, 3, 4}

Restricted Oxygen Intake

Some new, emerging research shows that there’s a connection between hypoxia (low levels of oxygen) and depression.¹² This may be because hypoxia affects serotonin in the brain, and it could also exacerbate anxiety symptoms, including panic and hypervigilance. As we know, there is a strong relationship between anxiety and depressive disorders.

The Effects Of Depression-Induced Cerebral Damage

Depression creates brain changes. For example, people with depression have chemical bioreactions, and they also lose gray matter volume in the brain. With that, depression-induced cerebral damage can affect someone’s emotional and executive functioning. It can affect mood, memory, cognition, sleep, appetite, emotional regulation, and susceptibility to physical and mental illness.

Sleep Disturbances & Emotional Issues

Research shows that sleep issues are one of the core features of depression, with nearly 75% of people with depression experiencing insomnia symptoms. Sleep issues can magnify depression, and depression can magnify sleep issues. This relationship likely has to do with disruptions in circadian rhythms, which are determined by the brain.¹³

Lower Cognitive Abilities

Cerebral damage may result in cognitive impairment. The brain oversees cognitive function, which refers to how we obtain, process, and reason with information. This supports learning, memory, language, and impulse control. This is also observed in patients with traumatic brain injuries—they often experience significant cognitive disruption and attention problems.¹⁴

Difficulty With Memories

Research shows that people with depression have smaller hippocampal volumes. The hippocampus plays a critical role in memory, particularly in coding short-term memories and transporting them for long-term storage. Therefore, disruptions or abnormalities within the hippocampus can affect memory recall and the ability to make new memories, which may be heightened in cases of depression.¹⁵

Susceptibility to Illness

Studies indicate that depression may compromise the body’s immune system. This is likely because depression and stress enhance the production of corticoids and adrenaline. This makes people more vulnerable to developing illness. Moreover, physical symptoms have also been found to increase the length of someone’s depressed mood, and chronic pain can be a predictor for developing depression.¹⁶

Why Does Depression Change the Brain?

Research shows that the brain has high levels of plasticity, which refers to the ability to change function in response to stimuli. However, depression impacts this plasticity, with studies showing that depression affects changes within the prefrontal cortex, basal ganglia, hippocampus, and amygdala.¹⁷ Ongoing, untreated depression is associated with decreased brain activity.

Does Depression Change the Brain Permanently?

While more research is needed to determine whether depression can lead to permanent alterations in the brain, a number of studies provide a hopeful outlook. Specifically, studies have suggested that certain antidepressant medications can improve the neuroplasticity of the brain and boost the production of new brain cells. Research also suggests that cognitive behavioral therapy (CBT) for depression can trigger similar improvements in the brain.^{1, 3, 4}

Treatment Options for Depression

Seeking treatment for depression early seems to improve the long-term outlook for people who experience depression. Studies have found that the most significant abnormalities are seen in the brains of people who have been severely depressed for ten years or longer and haven’t sought treatment. Research suggests that at least 80% of people who seek treatment for depression see an improvement in their symptoms.^{3, 4}

There are a number of effective treatment options for people struggling with depression. Most involve therapy, medication, or a combination of the two.

Effective treatments for major depressive disorder include:¹⁸

• Cognitive behavioral therapy (CBT): CBT for depression is a structured therapy that teaches people how to adjust the way they think and behave over the course of 12-24 individual or group CBT sessions.
• Interpersonal psychotherapy (IPT): IPT is a form of psychotherapy that helps people address and resolve issues within their personal relationships to strengthen their relationships & support systems in 12-16 individual or family therapy sessions.
• Behavioral activation therapy: Behavioral activation is a form of therapy that encourages people who experience depression to schedule activities, social interactions, and goal-directed actions over the course of 20-24 individual therapy sessions.
• Electroconvulsive therapy (ECT): ECT is a form of therapy that uses electrical currents to stimulate different regions of the brain while under anesthesia.
• Antidepressant medications: Antidepressant medications like SSRIs and SNRIs are often prescribed for depression and work by stimulating the production of mood-boosting brain chemicals like serotonin, dopamine, and norepinephrine in the brain.

How to Cope With a Depressed Brain

Seeking professional treatment is the most important step for people struggling with depression, but there are additional things people can do on their own to improve their symptoms. Prioritizing an active, social, and healthy lifestyle is among the most important steps people who experience depression should take.¹⁹ Maintaining a positive mindset is also an essential step for managing depressive symptoms, as well as managing stress.⁶

Here are ten proven tips for how to cope with a depressed brain:^{16, 19}

1. Exercise regularly: Exercise can boost your mood and energy levels, which is why exercise is a natural antidepressant.
2. Spend more time outdoors: Spending time outdoors in nature can relieve stress, as well as improving your mood, and help you feel more awake and alert.
3. Go out with loved ones: Spending time with friends, family, and loved ones can also help to balance your neurochemistry in ways that reduce symptoms of depression.
4. Practice mindfulness: Mindfulness for depression involves the practice of devoting your full attention to the present moment and has been proven to benefit your mood and mindset.
5. Improve your mindset: Negative self-talk is like food for depression and sadness, and positive thoughts have the opposite effect, which is why a daily gratitude list or positivity list can be a great way to combat depression.
6. Get 7-8 hours of sleep: Too much or too little sleep can negatively impact your mental health, which is why it’s important to get 7-8 hours of quality sleep each night.
7. Use a creative outlet: Repressing your depression can worsen symptoms, which is why it’s helpful for people who experience depression to find a creative outlet like painting, writing, or making music to express their feelings in a healthy way.
8. Eat nutrition-rich foods: Food can impact symptoms of depression. Replacing empty calories and junk foods with foods high in nutrients is another great way to naturally combat the sluggishness, brain fog, and low moods associated with depression.
9. Reduce screentime: Excessive screentime can contribute to a low mood and lack of energy, and certain activities like social media use are especially harmful, which is why unplugging devices and lowering screentime can be an important step to overcoming depression.
10. Use sound therapy: Certain types of music or sounds like binaural beats can have a positive effect on your mood and cognitive functioning, especially if you struggle with a  mood disorder like depression.

When to Seek Professional Support for Depression

If you or a loved one is struggling with depression, it’s important to seek treatment early before your symptoms worsen. The longer your symptoms progress untreated, the more likely it is that you will develop severe impairments, including negative effects on your brain. A number of treatment options exist, meaning there are plenty of different options to suit a variety of needs and preferences.¹⁸

For example, people who don’t want to be on medication can often see improvements with depression therapy alone, especially if they begin soon after their symptoms begin. Many people begin their search for depression treatment online by using a therapist directory that allows them to narrow their search by location, insurance, and therapist specialization. Alternatively, an online therapy platform can be an excellent option for people who find it difficult to get out of bed due to depression or do not have a plethora of therapists in their area.^{1, 5, 7}