The Science of Major depressive disorder (MDD)

Visiting a friend yesterday, I saw him display certain characteristics which includes, restlessness, loss of appetite and interest in everything around him, loss of self-worth which I could say is a result of his guilty feelings, sadness, poor concentration amongst many other signs which has surely affected his daily activities, making him look depressed. The cause of him being in that state wasn’t news to any of us, as he had most of his funds invested in Terra (Luna), and lost all, I couldn’t stop to wonder why the brain was so fast to get to that depressing stage.

Genetics Could be a Factor

After reading this article on The American Journal of Psychiatry, will I say that my friend has the Chromosome 3p25-26 which is genetic and found in families causing over 40% of the total depression cases? Actually, it might be a factor, but I haven't seen him depressed before and since we are family friends, I could tell if I have noticed this in any of his family members, which I haven't seen in any before. I am someone who tries not to worry about things for long, so I often do not experience this, but the WHO says, an estimation of 3.8% of the world's population which is approximately 280 million people (which is bigger than the total population of Australia, Brazil, and Sweden combined) suffers from Major depressive disorder (MDD).

Monozygotic twin will share 100% genetic material, but this isn't the same for non-twin as well as Fraternal twin, as they share 50% of their genetic material. While they share genetic materials,research published at JAMA Network dating back to 1999, shows that there is 39% chance of identical twin having depression genetically. Fast-forward to 2018, in an article published by National Center for Biotechnology Information says that additive genetic influences in twins would have a 28% chance showing depression symptoms while unique environmental influence could be the amount to 72%.

If the percentage is low in Twins and I haven't seen families of my friend display signs of Major Depression (MD), then I could look into other options.

The Neurotransmiters and Depression

The brain is made up of neurons which are differentiated by synapses. These neurons transmit messages across one another as well as to target bodies, and are recieved through receptors. After messages are recieved by the receptors, the receptors interprets and sends back the messages in a process known as reuptake via the synapse to the neuron where they are reabsorbed and repackaged for use. These Messages are known as Neurotransmitter. An imbalance or problem with Neurotransmiters such as Serotonin, Norepinephrine, and Dopamine could lead to depression.

The Serotonin, Norepinephrine, and Dopamine Hypothesis

We could say that a patient with continuous moody display show signs of Major Depressive Disorder. The mood of a person could be attributed to Serotonin being depleted. Serotonin being the neurotransmitter responsible for body functions such as mood, sleep, sexual desire, digestion, nausea, and other mood related factors of the body.

Serotonin hypothesis has been in existence since the 1960s and it is believed that a deficit in Serotonin transmission in the brain which was then corrected by antidepressant drugs were the cause of MDD. Since Serotonin is important in cognitive phenotypic characteristics, if there is a reduction in the Serotonin produced by the serotonergic neurons, patient could fall into a depression state and in some cases suicidal.

Similar to the Serotonin hypothesis, a deficiency or reduction of the Norepinephrine Neurotransmitter could lead to depression. The Catecholamine hypothesis of affective disorders, published in 1969, has been used to explain this process, and resent researches has been going.

Dopamine, which I will call the satisfaction Hormone, also have a great impact on depression. Usually associated with pleasure and reward, but a reduction or imbalance in Dopamine could lead to depression

Confusing Symptoms of Depression Making Me Doubt my Understanding on Depression

In most cases, people tend to lose moral when they are depressed, while some tend to be more active although not to a particular goal. One confusing symptom of depression is appetite. Some depressed people will have a decreased appetite, while others will have an increased appetite, causing the depressed patient to eat with no satisfaction. Anxiety and Depression Association of Americas also states that people with anxiety and depression with Binge eating disorder are liable to have obesity.

My Thoughts

Depression can be a very difficult disease to cure, seeing that antidepressants used to treat them could cause depression as well. Depression either as a result of genetics, or external effect could lead to lack of productivity in humans and in some cases the patients suicidal. In my research, I start to wonder if it is possible for a person to get depressed as a result of continually staying around a depressed person? Although we know it isn't contagious, but moods and emotions can be attracted since they are mental. Since it is easy for a person laughing or telling jokes to make people around laugh, could it be possible that a person who is depressed allow other people to start exhibiting symptoms of depression?