The Brain, The Body, The Behaviour – Depression


What is depression?

It is reported that globally 350 million individuals suffer from depression. There are two main types of depression;

  • Recurrent depressive episodes; this is where an individual suffers from repeated depressive episodes, which can last for up to two weeks. Thier episode can be characterised as mild, moderate or severe, depending on the severity and length of their symptoms.
  • Bipolar disorder; used to be known as “mania”. This is where an individual has “up and down” episodes, ranging from depressive with the common symptoms of depression, to manic which is where the symptoms are the total opposite – impulsive and reckless behaviour, elevated mood, increased need for sleep, overactivity.

There is no set cause for depression. For some it is triggered by a life event; relationship breakdown, death in the family, stress at work, financial difficulties, etc. For others it may be a biological mechanism in their brain that will always be there. It is no less real for either individual and the brain activity in both is pretty much the same, dependent on their symptoms as everyone suffers from depression in different ways. We will look at the symptoms of depression later on in the post.

The Brain

First, let’s look at the brain. You see those brain scans on the internet sometimes, two scans side by side, one on the left all lit up with activity and the other all dull and dark with inactivity, and the caption saying “the left brain is an individual without depression, the other is an individual with”. Now i’m not saying the caption is lying, but in actual fact in an individual who is suffering from depression, some areas of the brain are underactive whereas others are overactive. This depends on the neurotransmitters that pass through the areas, and the neurotransmitters that are produced in the areas. Let’s rewind a bit, shall we?

Neurotransmitters are one of the most important parts of the system of your body called the central nervous system. The CNS contains the spine, the brain, and all your neurotransmitters. Neurotransmitters are chemicals can carry messages between your nerve cells in order to get your body to do stuff, produce stuff, feel stuff…everything. Depression is related to the imbalance of these chemicals. And there are different types too:

  • Seretonin: This is pretty well known when it comes to mental health. Whenever I have a depressive episode it’s the most spoken word by my GP, “you’re probably lacking seretonin, here, have a prescription for some drugs.” But it works. Seretonin is linked to feeling serene and hopefulness, and the antipressant drugss SSRIs work by increasing seretonin.
  • Glutamate: This is associated with learning and memory, however too much of it can lead to impulsive behaviour, anger and agitation.
  • GABA: Increases feelings of tranquility
  • Dopamine: Another one famous for GPs and mental health professionals. Dopamine is involved in a lot of shit, but when it comes to mood regulation it is involved in arousal and stimulation. It is also associated with rewards and feeling rewarded. Therefore low levels of this are not only linked to depression, but also substance abuse.
  • Endorphins: These helpful fellas are associated with relaxation and euphoria. They are released when the body is inflicted by pain and stress, in order to calm the body down again. They are also released through exercise, and are usually called the “feel good hormone”.
  • Noradrenaline: This is associated with the fight or flight response, which you may remember from my previous blog post on anxiety.  However too much of this neurotransmitter can lead to nervousness, and not enough of it can result in the body feeling tired and lethargic.
  • Norepinphrine: These neurotranmitters help regulate emotions and energy levels.

Now we’ve covered the main neurotransmitters involved in depression, let’s have a look at the areas of the brain that are over active and underactive and the consequences of this:

  • Thalamus -> The thalamus is located in the centre of the brain. It has many functions, but specifically it controls arousal and awareness in a person and in doing so it is also involved in sleep. It also has the job of stimulating the amygdala. The thalamus is overactive in individuals with depression.


  • Amygdala -> The amygdala is the centre of emotions for the brain, but it specifically is responsible for negative feelings. So as you can imagine, it is also overactive in depression.


  • Hypothalamus -> The hypothalamus is responsible for producing a couple of the neurotransmitters mentioned above – seretonin and norepinephrine. Within the hypothalamus, these neurotransmitters create pathways that are involved in mood, emotional expressions and appetite. This tends to be underactive in those with depression.


  • Anterior cingulate cortex -> This is part of the cingulate cortex which surrounds the frontal part of the corpus callosum. It deals with the emotional response to pain and also the regulation of anger and is overactive in those with depression._9017293
  • Prefrontal cortex -> This is at the front of the brain and is full of norepinephrine and seretonin, and is therefore underactive in those with depression.


The body

All of these areas of the brain and neurotransmitters clearly play key parts in an individuals emotions, but the body and physical health of an individual is also affected in depression

  • Cognitive changes -> An individual with depression may have trouble remembering things. There is also the risk of being unable to make decisions. This isnt because the individual is indecisive, they just simple lack the cognitive ability to make a decision due to their depression.
    Furthermore, some antidepressants have a side effect that the memory of an individual may be effected. Can’t bloody win.
    As mentioned above, glutamate is a neurotransmitter that is involved in memory. It is possible that if it is not functioning as normal this may cause memory changes. The anterior cingulate cortex is also involved in retaining pleasant memories. If this area is not functioning properly the individual may be less likely to recall pleasant memories, leading them to only remember the negative which may reflect on their mood.
  • Weight/appetite -> Appetite can change. You know yourself, if you’re not feeling 100% you may not feel like eating anything, or you might feel like raiding morrisons and eating everything in sight. Well, this is the same for those struggling with depression. Individuals may lose their appetite completley, or may feel like they need to use food in order to cope and try to make themselves feel better as many foods release endorphins (the feel good hormone, discussed above).
    This change in appetite, either way, can lead to weight problems – either anorexia related illnesses, or obesited related illnesses. It can also result in stomach aches, bodily aches, headaches, and nutritional deficiencies.
  • Cardiovasular problems -> Depression and stress can cause blood vessels to constrict (become tighter, and as a result smaller). This means blood pressure is increased which can raise the risk of cardiovascular diseases. Those with depression are more likely to die following a heart attack.
  • Immune system -> Those with depression have a weakened ability to fight of disease. This may be for several reasons, perhaps because the individual is not looking after themselves well, nutritional deficiences, or because the neurotransmitters that help immunity are not functioning as they should be.

The behaviour

Now we’ve looked at the bodily and brain(ly?) abnormalities of an individual with depression, it may be able to help us look at the common, face symptoms, used to diagnose having depression in the first place. You don’t just go to the doctors and say “I am lacking seretonin, give me a pill”. No, there are symptoms you have like any illness, and in the case of depression an individual is usually diagnosed with having depression when they have been experiencing a few of the following symptoms for two weeks or more:

  • Loss of interest in normal daily activities and a lack of motivation -> This is due to a lack of dopamine. A lack of dopamine means the individual feels less timulated to do the things they would normally do, it also means that they are not motivated by being rewarded as their reward system in their brain is not functioning properly.|
  • Irritability/nervousness -> This is a sign of having too much glutamate and noradrenaline. Too much glutamate is linked with agitation and anger, whereas too much noradrenaline is linked to nervousness. Also, those with depression very commonly also suffer from anxiety disorders too which is linked to the nervousness.
  • Negative moods -> This is the classic symptom of depression. It’s not just feeling sad, it’s feeling every negative mood you can think of – low, nervous, numb, angry, jealous, vindictive, tearful. It can be due to a lack of several neurotransmitters: seretonin, dopamine, GABA and endorphins. Thoughts of death or suicide can result from this consistent feeling of negativity and is the worst outcome for an individual with depression.
  • Feelings of fatigue -> This results from a lack of noradrenaline which is responsible for an individuals energy levels so too little of this leads to fatigue and tiredness.
  • Self-harm -> This results from constant negative moods, including sadness, hopelessness and anger. There are several reasons why people self-harm, none of them right or wrong, it’s just a horrible side effect of depression. However there is a theory that individuals self harm as it releases endorphins (the feel good hormone) as they respond to physical pain in order to help numb the body.


Now after listing everything that depression does to an individual, I want you to take a minute and think about anxiety as well (take a look at my previous post if needed). 60% of individuals with depression or anxiety also have the other illness too. Imagine having to deal with several of these combined symptoms on a daily basis – the mental symptoms, and the physical symptoms. Everyone suffers from depression and anxiety differently, but I’ll bet if you were asked to draw a few of these symptoms at random out of a hat you wouldn’t be overjoyed about having to cope with any of them.

Makes you think, right? That’s what these blog posts are about, to make people think, and to make people aware. Being depressed and anxious isn’t all “just in someones head”, it’s in their brain, which is a different. Individuals aren’t making this stuff up, they’re suffering, it’s in their biochemistry, and it’s not a weakness. It’s an illness just as much as a physical illness is. You wouldn’t stigmatise against someone who has asthma because their lungs are different to yours, so let’s not do it for someone with different brain chemistry either.


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