Major Depressive Disorder

We see here that in someone with MDD there is both an increase in MAO A and a decrease in R1 (Johnson et al. 2011)
We see here that in someone with MDD there is both an increase in MAO A and a decrease in R1 (Johnson et al. 2011)

 

 

 

 

 

 

 

 

 

Neurotransmitters bind to a receptor to initiate a reaction response.
Neurotransmitters bind to a receptor to initiate a reaction response.

 

 

 

 

 

 

 

Major Depressive disorder (MDD) is a disease that affects many adolescents and adults globally; according to the NIMH (National Institute of Mental Health) 6.7 percent of adults as well as 3.3 percent of adolescents 13 to 18 years old in the United States will experience MDD.  Characterized by feelings of hopelessness, guilt, fatigue and often thoughts of suicide, this disease can be harder to classify than other (Johnson et al. 2011)more physical) diseases.  The resurgence rate of MDD is 50 percent, so a “cure” could still only be temporary.  Research in the field of MDD has majorly focused on specific proteins to find to actual cause of MDD.

It had been discovered around 1960 that a certain protein was associated with MDD, an enzyme called monoamine oxidase A and B (MAO A and MAO B).  These enzymes are responsible for helping reactions in the brain that break down neurotransmitters.  Of the neurotransmitters that are broken down, serotonin and dopamine are shown to be broken down by MAO A; both of these neurotransmitters are shown to be important in regulating mood (Duncan et al. 2012).  Recent work in the field has tried to figure out how MAO A works and what other proteins affect MAO A.  Studies such as Figure 1 (Johnson et al. 2011) show us that there is an increase in MAO A as well as a decrease in proteins that regulate  MAO A such as, for example, a repressor protein called R1; this protein stops MAO A from functioning.  Since there is more degradation of serotonin by more MAO A and less R1 to stop MAO A from working, there is less serotonin and dopamine to regulate mood.  This is the predominant theory of mechanism  for MDD in research today, and new drugs are being developed to target the above mentioned proteins specifically.  Other theories of mechanism for the disease center around the neurotransmitters themselves and how their receptors are the cause of MDD (Hvenegaard et al. 2012, Peng et al. 2012).  As shown in Figure 2 (McCord 2003), neurotransmitters such as serotonin or dopamine bind to a receptor to initiate a response in an adjacent neuron to stimulate activity in that neuron; when the receptor is either damaged or not working this response doesn’t work and can cause MDD symptoms.  Researchers are also creating drugs to help these receptors interact with the neurotransmitters or to stimulate the receptor itself.  Only by studying all mechanisms of MDD and investigating all treatment options can we be closer to treating this disease.

3 Replies to “Major Depressive Disorder”

  1. The title is informative and immediately tells me what the page is about, without bogging me down in too much jargon from the get go. There is a minor typo in the first paragraph, the closed parentheses after “physical” should not be there. I like the way that I am given a brief overview of the history of researching MDD, which relays the scope of the research and gives context for the more recent work done on the disease. The charts at the beginning are a little jarring, since I do not know what they refer to at first, so perhaps placing them throughout the piece would be better aesthetically. Overall it is informative and accessible to someone like me who lacks a science background.

  2. This post was straightforward and the information was consistent and structured. It would do nicely to have the charts follow up after presenting the information but other than that, there were no difficulties in reading this. It was actually quite interesting to read the figures regarding MDD and the various factors that can both cause and treat the disorder. The biology and chemistry terms were presented and explained in a way that one may understand without complications and once mentioned, the terms were used in an example which further clarified their meaning and application.

  3. I agree that the charts would be easier to understand if they were more in the middle of the essay. But other than that, this was a very clear presentation. The scientific terms were intersperced with examples and language that I can comprehend and I found it interesting to read.

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