Highlights
- Chronic stress is a leading environmental risk factor and plays a major role in the development of major depressive disorder, although genetic vulnerability also contributes.
- Depression mostly affects brain areas that regulate emotions and control memory, thought processing, planning, and decision making.
- These brain areas are affected by changes in brain chemicals and communication pathways, nerve injury, brain inflammation, and possibly lower blood flow.
- Many of these changes are reversible with evidence-based treatment, in particular antidepressants, but also therapy, lifestyle changes, and, in severe cases, neuromodulation.
Major depressive disorder (MDD) is considered the most common mood disorder and is one of the
This article will look closely at the connection between depression and the brain, revealing a leading trigger of depression and effective treatment options.
Depressed Brain vs Non-Depressed Brain: What’s Different?
The way that the depressed brain is different from a typically functioning brain involves many complex factors, for example:
- Changes in the size of different brain parts.
- Disrupted activity in nerve pathways.
- Alterations in neurotransmitters and their effects, brain inflammation, blood flow, and oxygen supply.
Let’s start by looking at the areas of the brain affected by depression.
Depression Anatomy: What Parts of the Brain Does Depression Affect?
Many brain areas are affected and in different ways, resulting in the classic symptoms, which together are called major depressive disorder. We know this because it can be seen on functional magnetic resonance imaging (MRI) scans.
Hippocampus
This
Prefrontal Cortex (PFC)
Amygdala
This is the brain’s watchtower, triggering the alarm when danger is detected. In depression, this might happen repeatedly, causing worry, agitation, negative thought dominance, emotional outbursts, and constant high alertness.
Thalamus/Anterior Cingulate
This is the brain’s
Ventral Striatum
This area is
|
Region |
Role |
In depression, compared to the general population |
|
|
Change |
Everyday effect |
||
|
Hippocampus |
Memorizing Learning |
Possible volume decrease/increase |
Forgetfulness Learning issues |
|
Prefrontal cortex |
Analysing information Decision making Planning Strategizing Processing emotions |
Possible volume decrease/increase |
Indecision Impulsivity Inattention Mood swings |
|
Amygdala |
Threat detection Triggers a reaction to danger |
Possible volume decrease/increase |
Worry Agitation Outbursts Negative thoughts Being on high alert |
|
Thalamus |
Relays information Monitors information |
Altered signaling |
Sleep and appetite shifts |
|
Ventral striatum |
Anticipating and experiencing reward |
Decreased reward response |
Experiencing less pleasure than usual Decreased motivation |
Next, we’ll look even closer, at the brain cell level, and see what is happening in these different areas.
What Happens in the Brain During Depression
Depression affects the brain at different levels. So, what does depression do to the brain cells? Again, it’s more than one thing.
Stress Hormones and Inflammation
Some observational studies suggest that as much as
These high cortisol levels
Resultant MDD symptoms:
- Low energy
- Slow thought processing
- Tendency to be hyperalert
Brain Circuits
Parts of the brain communicate in two ways:
Structurally[8] : How the nerves are physically wired (the nerve starts here and ends there).Functionally[9] : How different parts of the brain interact to get a particular job done.
In the brain of someone with depression,
- Increased activity in the alarm system of the brain.
- Decreased activity in the logical and analytical part of the brain.
Resultant MDD symptoms:
- Poor ability to think, concentrate, or make decisions.
- Constant agitation, emotional outbursts, and being on high alert.
Neurotransmitters
Neurotransmitters are chemical messengers in the brain. They activate receptors to allow nerve cells to transmit signals in specific brain areas. Each neurotransmitter plays a different role.
Depression affects them in several ways:
- There are lower levels of neurotransmitters where they’re needed.
- Nerve endings have a decreased number of receptors.
- Neurotransmitters
don’t bind well[10] to the receptors.
So, basically, neurotransmitters are not able to do their jobs properly.
Serotonin
Serotonin is a
Resultant MDD symptoms:
- Low mood
- Negative thoughts
- Feelings like hopelessness and worthlessness
- Poor memory
- Fatigue
- Changes in sleep patterns
- Changes in appetite
Norepinephrine
Dopamine
Reduced Blood Flow to the Brain
Does Depression Cause Brain Damage?
In simplified terms, you may say that depression causes brain ‘damage.’
Studies[17] report that depression can cause nerve cell endings to break down, which increases the gap between nerves (synapses). This gap makes it harder for signals to pass from one nerve to another.A recent study[18] shows that the long-term effects of depression on the brain are a risk for Alzheimer’s disease and other dementias.
This sounds scary;
How to Support Brain Recovery in Depression
Now that you have a better understanding of the brain components affected by depression, it’s easier to understand how major depressive disorder treatments work.
Medications
As we’ve already touched on, antidepressants correct neurotransmitter imbalances, repair nerve damage, and form new circuits.
- First-line treatments are usually selective serotonin reuptake inhibitors (SSRIs), such as fluoxetine, sertraline, citalopram, and escitalopram, and are the most widely prescribed antidepressants.
- Serotonin-norepinephrine reuptake inhibitors (SNRIs), such as venlafaxine, duloxetine, and desvenlafaxine, might be the first choice if the person with depression also has a pain condition.
- Norepinephrine-dopamine reuptake inhibitors (NDRIs) like bupropion are considered if reward pathways are severely affected.
- Ketamine and esketamine may be considered when all other medication options have failed.
Psychotherapies
Because chronic stress is one of the main reasons people develop depression and remain depressed, teaching them skills to deal with stressful thoughts and triggers helps to break the vicious cycle.
- Cognitive-behavioral therapy (CBT) changes the negative emotions associated with abnormal thoughts into positive ones, thereby changing behavior.
- Interpersonal therapy (IPT) encourages people to identify patterns in relationships that cause distress and how to prevent them with better communication and problem-solving.
When paired with antidepressants, therapy helps to rewire the depressed brain with new circuits.
Neuromodulation
A quick note on these therapies for resistant depression.
Transcranial magnetic stimulation (TMS) uses magnetic pulses to stimulate areas of the brain that control mood. It seems to fix brain activity patterns that are out of balance because of depression.
Electroconvulsive therapy (ECT) delivers controlled electrical current to the brain to treat resistant depression. It’s thought to work by stimulating
Healthy Lifestyle
Lastly, a healthy brain is more likely to be a happy brain:
- Physical exercise boosts blood flow.
- A good night’s sleep reduces stress and allows the brain to rest, reset, and repair.
- Stable daily routines help the brain cope with or avoid stress.
- Reducing alcohol consumption keeps the brain alert and prevents rebound anxiety.
When to See a Clinician
Reasons you should seek professional help for depression would include:
- You are not functioning well at work or other areas in daily life.
- Your relationships are breaking down.
- You’re self-medicating with illicit drugs or excess alcohol.
- You’re seeing or hearing things that other people aren’t.
- You’re thinking about self-harm or suicide.
A healthcare professional will screen you by taking a history, using a PHQ-9 questionnaire, and excluding physical conditions that might mimic MDD.
You can get assessed for depression at MEDvidi through a virtual consultation. Book your online appointment today to get help in 24 hours.
If you’re experiencing suicidal or self-harming thoughts and require immediate assistance, contact a crisis hotline, such as 911, 988 suicide & crisis lifeline (toll-free), or Samaritans (116-123 or via chat).
FAQs: Depression and the Brain
What part of the brain controls depression?
What does a depressed brain look like?
If you look at a depressed brain on functional magnetic resonance imaging, you may expect to see certain areas are smaller than usual, such as the hippocampus and prefrontal cortex, and have decreased activity, while the amygdala is enlarged and has increased activity. However, these changes don’t necessarily occur.
How does depression affect your thinking?
Depression affects your thinking. It may become more difficult for you to process information logically and store it, as usual; this might lead to you being indecisive and impulsive, having poor focus or attention, being forgetful, and having learning difficulties.
How long does it take for the brain to heal from depression?
There is no set timeline for the brain to heal from depression; this is because there are too many individual factors involved. A few of these include the severity of the symptoms, the triggers, and the treatment advised.
