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Depression: The Deadly Killer from the Biological Perspective

Imagine a secret spirit that could take away something much worse than someone’s physical abilities but instead, their ability to care about anything. It would float from person to person and essentially take their ability to live away from then? Sounds like some kind of horror movie but it is unfortunately not. Approximately 7% of the population will experience depression at some stage in their life. 1.9 million children and adolescents are diagnosed with depression and 50% of people who die by suicide are diagnosed with depression. And it is not only detrimental to the individual. Depression is one of the biggest disablers to the economy. Not only does it prevent people from working but it also costs the US 70 billion in healthcare costs. This menace competes with heart disease and cancer but people still don’t know what it is.

When you ask the general bystander what depression is, most will explain it as being really sad. But don’t we all get sad? When explaining depression, it is important to highlight that mental illness and mental health are two very different things. Someone who is mentally ill has a complex biological deficit or dysfunction. Depression involves complications in neurochemistry, which then causes imbalances in the endocrine system, which produces hormones, and the immune system, which protects us from diseases.

Our genes (biological) our thinking patterns (psychological) and the environment we grow up in (social) then has an influence on all these factors, making the concept of mental illness very complicated indeed. Alternatively, everyone has mental health. It is our quality of life and our healthy balance of positive and negative emotions, influenced by our lifestyles. If you don’t take care of your mental health, you develop the risk of mental illness. This might take the form of experiencing long term sadness that becomes distressful, which is what we understand as depression. While it is more common in women and those with chronic physical illnesses, it should also be noted that depression also aggravates our risk of developing other health complications. For example, those with depression are four times more likely to have a heart attack compared to those who do not.

To take this a step further, depression can be understood through several symptoms that disable someone to continue living as they did before. These symptoms include a lack of motivation, an absence of pleasure in anything also known as anhedonia, constant fatigue, no appetite, difficulty concentrating,difficulty sleeping and of course, a profound sadness that lasts for a long period of time and is highly distressful or painful. If someone develops one of these symptoms, we can generally deal with it but combined, they are overwhelming and there is clearly something more than just the individual symptoms. This is depression. And this education is really important. Not only so the person suffering from depression knows when to seek help but also to stop the person taking up a space on a mental health clinic waiting list because they have been feeling sad the past few days. Know the difference. 

From a biological perspective, scientists believed that depression was caused by neurotransmitter (brain chemical) dysfunction. You are probably familiar with these neurotransmitters. They are known as monotones and they include norepinephrine, serotonin and dopamine. Now imagine these neurotransmitters are people who need to go to work. At the end of each brain cell, there is something known as a synapse and information is passed from this synapse to another through receptors.

So imagine the people need to go from the presynapse (home) to the post synapse (work). If everyone goes to work, our brains are working correctly. However, with depressed people, there is an increased number of receptors on post synapses (lots of jobs available) but nobody can get to work because the molecules that transport the information are not available. They are stranded. This is what neurobiologists understand to be depression and this is exactly what people refer to when they say there is a chemical imbalance. This theory has further advanced to take environmental factors into account. It is now understood that some people may have a genetic vulnerability to this brain imbalance. However, it has to be activated and it is done so by stress hormones. This is where therapy comes in. If people have a genetic vulnerability to this chemical imbalance and they are unable to deal with stress, more of the stress hormone, known as cortisol is secreted and this combination is what could lead to depression. If the stress hormone is constantly being secreted but there isn’t a chemical imbalance, one then possibly suffers from poor mental health. If someone has the brain imbalance paired with a constant over secretion of the stress hormone, these changes in the body can facilitate depression.

Antidepressants such as Prozac or SSRIs (selective seretonin reuptake inhibitors) then make neurotransmitters last longer by stopping serotonin staying in the pre-synapse (home) and ensuring an increased likelihood that serotonin goes to the post synapse (work). Therefore, they allow the people to do more work, kind of like a HR rep. However, the neurochemistry of depression is far more complicated than this and this is why antidepressants are not always effective.


The inability for society to appreciate depression because it cannot be seen is costing society and individuals everything. It is disappointing that even the visible consequences of depression such as disability to work and suicide are still not enough. However, the biological perspective is giving us a more objective view of the illness and researchers are making progress in fighting against this demon. At the moment, the best we can do is educate ourselves about it. Understanding the biological mechanisms behind depression makes it very visible. We can see depression. We just need to look in a different way. Know the symptoms and seek or advice help when you see them.   Yours sincerely, The Motus Movement. 


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