9 Facts About Serotonin – Can this substance be a cause of depression?

We at psych2go have prepared a handy list of facts about the relationship between serotonin and depression because we noticed some people were confused about how the two are related. Are there differences between male and female? Where is serotonin made? What are SSRIs? Neurotransmitters such as serotonin can be very confusing, and there are many myths about them, but we are here to help you out!

  1. What is it?

Serotonin is a neurotransmitter, a type of chemical that functions in processing signals within the brain. It helps to bring signals from one area to another. There are many different neutransmitters with many different functions.

working neurotransmitters such as serotonin are involved in all our brain activity
  1. What does it do?

It’s quite hard to define what the exact function is, as – being a neurotransmitter – it helps with relaying many different signals, and in this way can have many different effects. Serotonin is believed to influence a variety of psychological functions, from mood, appetite, sleep, memory, even sexual desire and more physical functions.

  1. Where is it made and where does it go?

It is made in the brain and performs its main functions there, but surprisingly, up to 90% of serotonin is found in the blood platelets and digestive tract.

brain activity
happens because of neurotransmitters
  1. What does it have to do with mental health?

Many studies point towards a relationship between imbalanced serotonin levels and depression. As a neurotransmitter if performs a variety of psychological and other bodily functions, of approximately 40 million brain cells, most of them interact with it in some way or other. In this way the substance can have effects on mood, sexual desire and function, appetite, memory, learning, sleep and others.

Possible problems of a serotonin imbalance can also extend to other things along the mental health spectrum, such as OCD, anxiety, panic attacks and even flares of anger.

  1. Then how can an imbalance cause depression?

Some theories state that the relationship between serotonin and depression lies in the fact that serotonin is believed to have an effect on the birth and death of cells in the brain area. According to Barry Jacobs from Princeton , stress can inhibit the production of new brain cells, and that stress is a very common precipitator of depressive episodes. He researches how medication that is commonly prescribed in cases of depression, called SSRIs can help get out of the imbalance.

  1. What is an SSRI?

explanation of working serotonin and SSRIs

SSRI stands for Selective Serotonin Reuptake Inhibitor. When a signal is passed in a neuron, it will eventually reach the ‘edge’ and have to pass it on to the next. This scene is shown in the image above. When the signal reaches that site, the neuron that passes the signal (presynaptic) will release the neurotransmitter, in this case serotonin. It will ‘hang’ in between the neurons and the next neuron will ‘sense’ – with it receptors – that a signal has been given and start passing it on. The serotonin left behind is once again taken up and sometimes broken down so its parts can be reused. This happens within a fraction of a fraction of a second.

However, sometimes this reuptake process happens too quickly, not leaving enough to help reach the ‘sensing border’ (threshold) of enough serotonin to have the next neuron pass on the next signal properly. This is called an imbalance, as there isn’t enough serotonin left. What SSRIs can do is block or inhibit the reuptake sites, which slows the reuptake process, leaving more serotonin available for the next signal.  Though this is what process takes place, it’s not completely clear how exactly this works on depression. But it has been researched at length, and it does help with depression in most cases.

  1. So what are the research limitations showing?

People with depression have lower blood levels of this transmitter. However, it’s not quite clear in how these reflect the serotonin levels in the brain. It’s also uncertain if the two are strongly or weakly related. There is not yet a way to measure the levels within a living brain, so researching it is tough. It’s also not completely clear whether serotonin causes depression, or if depression causes serotonin levels to drop.

  1. Is there a difference between people who are biologically male or female?

Yes there is actually. Biological males have slightly higher levels, but the difference is thought to be negligible. However, a 2007 study suggested that how their respective brains react to a decrease in serotonin is what makes a difference. The brains of those biologically female showed more effect from the same decrease in serotonin. This suggests it might be one of the reasons depression is more common in females.

  1. So does serotonin play a role in causing depression or not?

Some claim it’s a myth, but that is not the right word. Some claim an imbalance definitely causes depression, but that is not right either. Research tells us that when there is a case of depression, serotonin imbalance is often present too. Whether this is the cause of or a result of depression is not quite clear yet. It is hard to research with the current technologies.

  1. What do you think about this? Do you think this neurotransmitter imbalance is (partly) a cause of depression or a result?
  2. Would you like more articles explaining how certain hormones or neurotransmitters work?
  3. Would you like more articles on how certain types of medication behave in the body

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  1. This has to be one of the most interesting articles I’ve read on here so far! Although this may be in part to the fact that it’s rather relevant to me in this time of life – as I’m trying to get medication for anxiety and depression. The way this article was set up is wonderful, and it gives incredibly useful information that actually left me with my own questions about depression and seretonin – I’d love to see more research done into this topic!

  2. This was great and so informative! I’m glad this article was written to clear up some confusion, and that it did so in an unbiased way. I also really liked that it acknowledged the fact that we don’t know if depression causes low serotonin or if low serotonin causes depression, and that there is much else we don’t completely understand about the topic. It was very informative and straight to the point.
    I noticed just a few technical errors. In question number 3 ‘bloot’ platelets was written instead of blood platelets (this kinda cracked me up though). And in question 4 the last sentence of the first paragraph was a little confusing and could use some rewording. Over all it was great!

  3. Very clear and to the point, well done! Bolded questions helped readers to not read just a block of text, and I love the questions you asked in the introduction on which readers might be curious about, great job!

    One thing I can suggest is maybe reading your article aloud. Not only will this help understand what you, yourself, wrote as a writer, but to also catxh tiny mistakes here and there in case you might’ve overlooked something involving grammar.

    Other than that, well done! keep it up!

  4. This was extremely well written in a scholarly manner. The article was very informative and I learned alot of information I didn’t even know I needed to know. More articles like this would be well appreciated.

  5. For someone who cares about mental health issues, I’ve always heard about the serotonin imbalance thing but never fully understood it, so this helped clear some things up for me. Science is always a process and I like that this didn’t have a clear cut answer and just showed us the facts that are present so far and how they’re being interpreted. I did get a little confused when you discussed how stress can often inhibit the growth of new brain cells and serotonin can play a part in that which then leads to depression? So is depression just the effect when new brain cells are not being produced at the right rate for each person? That might not be what you’re saying but I got slightly confused so maybe try and re word that so it is more clear.

  6. This was a very educational article. I appreciated the actual facts that were displayed in this article and as someone who has learned about serotonin and SSRIs etc, I thought there were decent explanations for someone who does not understand what they are. I wish I had these more simple explanations in college just to understand the basic mechanisms of things! I appreciated that the article made sure not to push the idea of cause and effect because we all know that causation is not equal to correlation and it is extremely difficult to prove causation due to other variables and difficulties measuring the different variables. This was a quick read, but was packed with information. I definitely like these types of articles that focus on just one thing, even if it is as small as just one neurotransmitter, it makes it easier to gain knowledge about one thing than some knowledge about a variety of things.


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