What Causes Depression In The Brain


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If My Mother Or Father Was Depressed Will I Be Depressed

How Depression Affects The Brain – Yale Medicine Explains

Depression can be transmitted in families in several ways. Parents and children may share an array of genes that create susceptibility to depression. Even more subtly, parents may engage in depressive thinking and explanatory styles that children acquire unwittingly in the air they breathe every day at home while growing up.

There is considerable evidence that when mothers of young children are depressed, they fail to engage with their children. As a result, babies do not acquire the strong emotional bond that enables them to grow, to withstand stress, to develop emotional regulation, and to become responsive to others. Treating depressed mothers is often the best way to treat problems in children.

Immune System & Inflammation

Inflammation is the bodys response to a perceived threat, such as a cut or infection. When it becomes widespread or chronic, it can wreak havoc in the body and brain. In fact, studies show that chronic, low-grade inflammation is associated with increased risk for depression and other mental illnesses. Possible sources of inflammation include poor diet, stress, changes in the gut microbiome, and certain medical illnesses.

Brain Regions And Mood

Popular lore has it that emotions reside in the heart. Science, though, tracks the seat of your emotions to the brain. Certain areas of the brain help regulate mood. Researchers believe that more important than levels of specific brain chemicals nerve cell connections, nerve cell growth, and the functioning of nerve circuits have a major impact on depression.

Increasingly sophisticated forms of brain imaging such as positron emission tomography , single-photon emission computed tomography , and functional magnetic resonance imaging permit a much closer look at the working brain than was possible in the past. An fMRI scan, for example, can track changes that take place when a region of the brain responds during various tasks. A PET or SPECT scan can map the brain by measuring the distribution and density of neurotransmitter receptors in certain areas.

Use of this technology has led to a better understanding of which brain regions regulate mood and how other functions, such as memory, may be affected by depression. Areas that play a significant role in depression are the amygdala, the thalamus, and the hippocampus .

Figure 1: Areas of the brain involved with depression

The regions shown here are mirrored in both hemispheres of the brain. Also, these structures are interlocking the illustration suggests relative position but not precise location.

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How Does Loneliness Lead To Depression

Loneliness assaults the body and mind in multiple ways. By itself, it is felt as a major stress, and is linked to the release of stress hormones, which are known to impair such brain operations as learning and memory retrieval. Whats more, loneliness magnifies the perception of all other stresses. It diminishes functioning of the immune system and readily leads to inflammation, a known pathway to depression.

The emotional discomfort of loneliness makes us feel sad, and sadness saps our energy and slows functioning of all body systems. Companionship is such a powerful buffer to all human difficulty that loneliness is said to have even more of a detrimental effect on health than cigarette smoking.

Temporal Aspects Of Depression And Drug Strategies

Depression Brain

Not only are there different subtypes of depression, but the disease too has a temporal aspect that is not well understood. Some people experience depression for short periods of time, and others can be depressed for years. In a new study published April 11, 2019 in Science, Liston and his lab looked at the neurobiological mechanisms underlying the induction and remission of depressive episodes.

For this project, the researchers relied on mouse models and optogenetic tools. What we set out to do was follow, track, and quantify the remodeling of synapses in the living brain, using advanced imaging methods in mice, says Liston. The researchers tracked these synapses in real-time, watching how they were affected by stress and antidepressants.

Going into the study, Liston knew that antidepressants increased synapse connections. The connection between depression and synapse loss and formation, however, was unclear. The question the researchers wanted to answer was this: Are the two causally involved or merely correlated?

Working with Haruo Kasai and Haruhiko Bitocollaborators at the University of Tokyo who developed optogenetic tools for deleting new synapsesListons work was able to show that new synapses are required for sustaining antidepressant behavioral effects and maintaining remission over time. Interestingly, however, the synapses were not necessary to induce behavioral changes initially.

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Depression Treatments On The Horizon

Researchers are studying other molecular pathways in the brain to see what role they may play in depression. It may be that rather than a simple deficiency in one specific brain chemical being the causative factor, some depression symptoms could be related to the relative levels of each type of neurotransmitter in different regions of the brain.

Rather than being a simple equation of some unknown factor causing low levels of one or more neurotransmitters and these low levels creating the symptoms of depression, the actual basis of depression is much more complex. While this complexity is often evident to people living with depression, medical professionals and researchers are still trying to understand the intricate nature of diagnosing and treating the condition.

For example, in addition to the role of neurotransmitters, we know there are multiple factors involved in causing depression ranging from genetic factors and childhood experiences to our present day-to-day lives and relationships. Even inflammation is being explored as a potential contributing factor.

How Do Thinking Styles Influence Depression

Brooding over mistakes or unpleasant experiences, jumping to catastrophic conclusions from one or two setbacks, overgeneralizing from limited evidenceall are errors of thinking, or cognitive distortions, strongly linked to depression.

Such thinking mires the brain in negativity and, if unchecked, breed self-doubt and hopelessness. Whats more, studies show that negative thinking styles such as catastrophizing actually change physiology. Researchers have found that they enhance reactivity to painful stimulation and raise levels of the stress hormone cortisol and of pro-inflammatory agents in the blood. The inflammatory response brings on behavioral changes commonly associated with both sickness and depressionfatigue, slow reaction time, cognitive sluggishness, and loss of appetite.

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Does Anxiety & Depression Cause Brain Fog

Anxiety and depression are among the most common mental health disorders experienced in the US. In fact, over 40 million adults in the US have an anxiety disorder, and 17.3 million struggle with major depressive disorder . Anxiety and depression can impact physical health and have long-lasting effects on the individual and their loved ones.

Brain fog can occur as a result of these mental health conditions or stress. Brain fog from time to time is a normal experience. However, brain fog can become a recurrent problem that interferes with daily functioning when it is caused by depression or anxiety.

The Experts At Harvard Medical School Help Us Understand Depression

What Causes Depression.mov

It’s often said that depression results from a chemical imbalance, but that figure of speech doesn’t capture how complex the disease is. Research suggests that depression doesn’t spring from simply having too much or too little of certain brain chemicals. Rather, there are many possible causes of depression, including faulty mood regulation by the brain, genetic vulnerability, stressful life events, medications, and medical problems. It’s believed that several of these forces interact to bring on depression.

To be sure, chemicals are involved in this process, but it is not a simple matter of one chemical being too low and another too high. Rather, many chemicals are involved, working both inside and outside nerve cells. There are millions, even billions, of chemical reactions that make up the dynamic system that is responsible for your mood, perceptions, and how you experience life.

With this level of complexity, you can see how two people might have similar symptoms of depression, but the problem on the inside, and therefore what treatments will work best, may be entirely different.

What follows is an overview of the current understanding of the major factors believed to play a role in depression.

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Dopamine And Depression Neurotransmitter

Dopamine is a neurotransmitter in the brain that many people refer to as the pleasure neurotransmitter. Its produced in the body when L-Tyrosine is converted into L-DOPA, the precursor to dopamine. Dopamine also acts as a hormone in the blood.

In the brain, dopamine is responsible for that sense of accomplishment we get when we achieve something and the motivation that keeps us going. Its not only linked to pleasure but to reward and reinforcement — such as that feeling we get when someone complements our outfit.

Most people living with depression are also experiencing low dopamine levels, especially when serotonin-related antidepressants arent working . Thats why dopamine medication is often used in addition to serotonin medication.

Why Does A Major Depressive Disorder Change Your Brain

When you suffer from depression, your brain is physically changed. Research by the National Institutes of Health shows that you lose gray matter volume when you suffer from depression. This loss is caused by parts of your brain shrinking due to the hormone cortisol impeding the growth of your brain cells.

The more serious depression a person suffers, the more GMV they lose. Since GMV contains most of your neurons or nerve cells, slowed growth means that your cognitive capabilities are at risk of impairment.

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What Is The Biochemical Basis Of Depression

Steven Gans, MD is board-certified in psychiatry and is an active supervisor, teacher, and mentor at Massachusetts General Hospital.

There are several theories about what causes depression. The condition most likely results from a complex interplay of individual factors, but one of the most widely accepted explanations cites abnormal brain chemistry.

Sometimes, people with depression relate the condition back to a specific factor, such as a traumatic event in their life. However, it’s not uncommon for people who are depressed to be confused about the cause. They may even feel as though they don’t have “a reason” to be depressed.

In these cases, learning about the theories of what causes depression can be helpful. Here’s an overview of what is known about how chemical imbalances in the brain may influence depression.

Causes Of Low Neurotransmitter Levels


If low levels of neurotransmitters can contribute to depression, an important question is what causes the low levels of serotonin, norepinephrine, or dopamine in the first place? When there is a breakdown anywhere in the process, low levels of neurotransmitters can result.

Research has indicated several potential causes of chemical imbalances in the brain, including:

  • Molecules that help make neurotransmitters are in short supply
  • Not enough receptor sites to receive the neurotransmitter
  • Presynaptic cells are taking the neurotransmitter back up before it has a chance to reach the receptor cell
  • Too few of the molecules that build neurotransmitters
  • Too little of a specific neurotransmitter is being produced

Several emerging theories are concerned with the factors that promote lowered levels, such as cellular stress. But one of the main challenges for researchers and doctors hoping to connect depression to low levels of specific brain chemicals is that they don’t have a way to consistently and accurately measure them.

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What Are The Most Common Causes Of Depression

Studies consistently show that depression is most associated with the number of stressors experienced in life, and the effect is cumulativethe more stresses that accrue over time, the greater the likelihood of getting depressed. The loss of an important relationship by death or divorce is experienced by most people as a major stress requiring significant adjustment.

Loneliness is both a physical and emotional stressor, and rates of loneliness, known to be high among the elderly, are sharply rising among the young, who increasingly report having no close friends. Job loss or the threat of job loss are almost invariably sources of constant worry. In the absence of a wide array of coping skills, even minor bumps on lifes journey can become significant stressors.

Seasonal Affective Disorder: When Winter Brings The Blues

Many people feel sad when summer wanes, but some actually develop depression with the season’s change. Known as seasonal affective disorder , this form of depression affects about 1% to 2% of the population, particularly women and young people.

SAD seems to be triggered by more limited exposure to daylight typically it comes on during the fall or winter months and subsides in the spring. Symptoms are similar to general depression and include lethargy, loss of interest in once-pleasurable activities, irritability, inability to concentrate, and a change in sleeping patterns, appetite, or both.

To combat SAD, doctors suggest exercise, particularly outdoor activities during daylight hours. Exposing yourself to bright artificial light may also help. Light therapy, also called phototherapy, usually involves sitting close to a special light source that is far more intense than normal indoor light for 30 minutes every morning. The light must enter through your eyes to be effective skin exposure has not been proven to work. Some people feel better after only one light treatment, but most people require at least a few days of treatment, and some need several weeks. You can buy boxes that emit the proper light intensity with a minimal amount of ultraviolet light without a prescription, but it is best to work with a professional who can monitor your response.

There are few side effects to light therapy, but you should be aware of the following potential problems:

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Medication Recreational Drugs And Alcohol

Depression can be a side effect of a lot of different medicines. If you are feeling depressed after starting any kind of medication, check the patient information leaflet to see whether depression is a side effect, or ask your doctor. If you think a drug is causing your depression, you can talk to your doctor about taking an alternative, especially if you are expecting your treatment to last some time.

Alcohol and recreational drugs can both cause depression. Although you might initially use them to make yourself feel better, or to distract yourself, they can make you feel worse overall. See our pages on the mental health effects of recreational drugs and alcohol for more information.

What Can I Do If I Have Depression

What Causes Depression and Low Mood? | Clinical Psychologist | Living With a Brain Tumour

If you have symptoms of depression, see your healthcare provider. They can give you an accurate diagnosis, refer you to a specialist or suggest treatment options.

If you or someone you know is thinking of hurting themselves or taking their own life:

  • Go to the emergency department of your hospital.
  • Contact a healthcare provider.
  • Speak to a trusted friend, family member or spiritual leader.

A note from Cleveland Clinic

Depression is a common condition that affects millions of Americans every year. Anyone can experience depression even if there doesnt seem to be a reason for it. Causes of depression include difficulties in life, brain chemistry abnormalities, some medications and physical conditions. The good news is that depression is treatable. If you have symptoms of depression, talk to your healthcare provider. The sooner you get help, the sooner you can feel better

Last reviewed by a Cleveland Clinic medical professional on 12/31/2020.


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Key Neurotransmitters And Depression


  • Norepinephrine is a neurotransmitter and a hormone that sends flight or fight messages throughout different cells in our brains. It also plays an important role in how our brains and bodies process and interpret the hormone adrenaline. Located in our sympathetic nervous system, which controls our bodys rapid, involuntary responses to dangerous or stressful situations, norepinephrine is also known for constricting blood vessels and raising blood pressure.


  • Serotonin helps regulate our mood. It also sends messages throughout the brain that let us know when we need to eat, digest, and sleep. In addition to that, serotonin sends signals that reduce pain, regulate anxiety, stimulate nausea, heal wounds, and block pain, too. Despite what most of us might think, most of the serotonin in our bodies is in the gut, not the brain. Regardless of that, serotonin plays a central role in relaying messages about our emotional state.


  • Known as a feel good chemical, dopamine sends positive signals related to reward. When dopamine transmits a message between our neurons, our brains receive positive reinforcement and were encouraged to perform that dopamine-triggering activity again. Because dopamine sends pleasurable messages between nerve cells, this neurotransmitter helps motivate us and stimulates our interest in certain activities, people, and places.

Other neurotransmitters that affect our emotions and mood include:

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How Does Perfectionism Lead To Depression

Perfectionism is like an endless negative report card. Those in its grip dont just hold high standards for themselves, they are perpetual self-critics, always judging themselves harshly. They focus on the very thing they most want to avoidnegative evaluation and failure. Perfectionism keeps people completely self-absorbed, always finding fault with themselves, a mindset that prevents them from taking on potentially-rewarding challenges.

Even when perfectionists complete a task, they cannot enjoy a sense of achievement relentless concern with mistakes leads them to be haunted with uncertainty about their performance. The constant negative focus leads to a negatively distorted view of themselves, self-doubt, and feelings of inadequacy and worthlessness. Perfectionists are vulnerable to depression because their self-worth is contingent on fully achieving goalsa condition that, by definition, they can never meet.

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