Why Depression Isn’t Just a Chemical Imbalance

[ ♪INTRO ] Chances are that you or someone you care about
has experienced depression. It’s one of the most common mental health
problems in the US. Around 16% of American adults will suffer
from depression at some point in their life. Given how much we talk about and treat depression,
it might seem like we’ve got it figured out, from a scientific perspective. But we do not understand as much about it
as you might think. Especially what’s actually going on in your
brain when you’re depressed. Doctors have defined depression, or at least
agreed on a set of criteria to diagnose it. The Diagnostic and Statistical Manual for
Mental Disorders, also known as the DSM, is the handbook healthcare professionals use
to diagnose mental disorders. And the latest edition of the DSM lays out
two key symptoms of depression. The first is feeling sad or depressed. But many depression sufferers experience this
more as a lack of feeling, or numbness, rather than sadness. The second is a loss of interest or pleasure
in activities that are normally enjoyable. You have to have at least one of these key
symptoms, as well as 3-4 additional symptoms consistently, to be diagnosed with depression. Additional symptoms can include unpleasant
things like: feeling worthless, difficulty sleeping or sleeping too much, difficulty
concentrating and making decisions, or suicidal thoughts. Not all of your symptoms need to be severe,
but as a group they can make it harder for you to function at work or school, in your
relationships, or just in life. We know that depression isn’t simply a bad
mood that you can snap out of — something is not functioning correctly in your brain. The question is what? One widespread impression among the public
is that depression is caused by having too little serotonin. But that’s an oversimplification at best. Serotonin is a neurotransmitter — a chemical
that neurons use to signal each other. When a neuron signals its neighbor, it releases
a neurotransmitter, like serotonin, into the synapse — the space between itself and its
neighbor. The serotonin molecules diffuse across the
synapse and bind to their receptors on the neighboring neuron, transmitting the signal. Then the signalling neuron reabsorbs — or
re-uptakes — its serotonin. Some of the most commonly used medications
for depression are selective serotonin reuptake inhibitors, or SSRIs. SSRIs reduce the reuptake of serotonin, which
increases the amount of serotonin hanging around synapses. But how these medications work and sometimes
don’t work show that a lack of serotonin isn’t the only thing happening in the depressive
brain. If that were true, you’d expect that SSRI
medications to work pretty quickly, and to work for everyone with depression — but
they don’t. Even though serotonin concentrations may go
up right away when you take an SSRI, it can still take weeks for people to start feeling
better. That is, if they even start feeling better
at all. SSRIs simply don’t work for all patients. Research has identified a few other potential
factors that could help us better treat depression. First off, serotonin isn’t the only neurotransmitter
that plays a role. Research has shown that at least 5 other neurotransmitters
could be involved, all of which serve many different functions in the brain and elsewhere
in the body — it’s complicated! And the structure of our brains matters too
— not just the chemicals inside them. Certain regions of the brain, and the connections
between them, have been shown to be altered in depression. The amygdala, which helps us process emotions,
and the hippocampus, which has a role in memory storage, are among the brain regions that
undergo structural changes in some patients with depression. Changes like having a different size compared
to people without depression, though we’re not sure what that means exactly yet. And rather than merely changing the levels
of certain neurotransmitters, studies have shown that antidepressants can actually help
new neurons grow in certain parts of the brain. Which may be one reason why SSRI medications
typically take so long to work. Your brain could be growing new neurons, not
just responding to a short-term change in chemical messengers. There’s likely a genetic component to depression
as well. There is some evidence that depression can
run in families, though the association isn’t particularly strong. A 2018 genome-wide study sampled a huge pool
of genes in people with and without depression. It found 44 variants that seem to be associated
with depression. These so-called “genes of interest” included
genes previously shown to have a role in the growth of neurons — as well as some surprises,
like genes previously shown to be involved in immune system function. But it’s unlikely that a particular gene
or genes cause depression on their own. More likely, it could be the result of how
your personal set of genes interacts with your environment and your experiences. Some studies have found that variants in certain
genes can interact with major stressful events in childhood to affect the rate of depression
in adults. But not all studies find such strong links
between our genes and our environment. It’s still an active area of study. So depression is hard to figure out. There are so many factors involved, and they
all interact with each other — from genetics and environment, to the chemistry and structure
of the brain. The good news is that even though we don’t
entirely understand how depression works, we still have ways to treat it that help lots
of people. You don’t have to know exactly how an existing
medication or treatment works to know that it does work — that patients may respond
to it and feel better. Meanwhile, scientists are still working to
tease out the many, intertwined causes of depression to develop new treatments. So there’s hope on the horizon. Even when you can’t see it. Thanks for watching this episode of SciShow
Psych, which was supported by our community of patrons. To learn more, check out patreon.com/scishow. [ ♪OUTRO ]

About the author


  1. can you be depressed without initially knowing it, and with some days that are mostly ok? The last few years I've had a lot of months where I just felt tired, apathetic, worthless and without purpose. These feelings were once or twice a week alternated with a day that felt pretty ok or even good, and sometimes even a few days like that. But overall I just felt pretty 'meh' and 'blegh'.
    It doesn't matter all that much now because I'm slowly coming out of it, but I'm still kinda curious about it, and questioning if I should've gone to a psychologist.

  2. I've been through horrible depression. I think a large aggravating factor is environment, particularly capitalism. We are in a culture of greed and alienation; it's no surprise that depression rates are rising yet extremely low in tribal communities.

  3. 1. Why did the serotonin neurotransmitter ever get associated with depression? It appears to be more of a meme and a marketing concept than actual scientific fact. http://cepuk.org/unrecognised-facts/myth-of-the-chemical-imbalance/

    2. This video almost barely references nurture at all. Why is depression not being examined AS A SYMPTOM, rather than as a disease? It is anecdotal, but, out of all the people I’ve met who self-described as depressed or who have been diagnosed with “clinical depression”, not a single one of them LACKED evidence of experiential causation (trauma, abuse, long-term or perpetual stress, lack of agency in their lives, etc). IE: none of them were “depressed for no reason”. They may not have recognized their experiences as being particularly toxic, and many were quite acculturated into belief (whether through family or wider culture) that their toxic experiences were somehow “normal”. http://cepuk.org/unrecognised-facts/no-biological-causes/

    Note: SSRI/SSNRI drugs not only “don’t work for some people”, they can make some people lose impulse control and even destroy their lives as a consequence. As serotonin is associated with inhibitory function, meddling with this function can lead to the adverse effect of suicidality, resulting in (among other horrible things for victims of this) a “black box” warning being applied to SSRI/SSNRI drugs around 2005(?). Suicidality is not the only consequence (it’s just the most striking example of loss of impulse control, aside from acts of violence). Relationships destroyed, jobs lost, addictions started (aside from the SSRI/SSNRI, which is physiologically addicting), gambling problems, shopping sprees, bankruptcy, and even violence.

  4. My ex broke up with me because she's numb to feeling anything. I'm devasted because I don't know how to help

  5. I’m currently going through depression. ever since I was 15 I had depression and I’m currently 18. I have had less episodes but they have become much more intense and last a lot longer. I can’t function and all I do is stay in my bed and I hate it but I just can’t stand anything else around me. School has been hell because I can never do anything and I don’t mean that I’m too lazy i mean I physically and mentally literally can’t do it. I don’t even think I should do college because I’m pretty sure I’m just not ready yet. But my parents are forcing me to go I don’t know what to do

  6. Depression is a result of the post modern obsession of happiness instead of duty. Of pace and lack of meaning. Of medical waywardness, diet and exercise. Respect your body and your mind, shrug off modernity and losers, and get all those bad experiences out in the open. Harness hope by doing things you enjoy and setting goals for change.

  7. What if someone’s depression is just philosophically driven and it can’t be treated without the person lying to their self? Like, nihilism that only wavers when you tell yourself an answer for hopelessness, when that answer then falls flat upon closer inspection just a week later.

  8. My friend has short periods of depression sometimes, where she’s really depressed for a few days and than returns to normal. In some people there seems to definitely be something more at work.

  9. Depression is a reaction to environmental factors. It is based on the primitive instinct to migrate or change environments when certain environmental ques are triggered (example change in season). Culture has evolved to a point where is disregards primitive instincts as "mental illness" or abnormality. A mother of 3 who has been married in a Christian home and is depressed could benefit from just up and leaving and changing environments. However, this is discouraged as it causes economic instability in society. If we allow people to migrate or change environments to quell these internal ques, known here as depression, then it would conflict with modern economic standards, which are heavily founded on staying put and living a certain way for the entirety of your life. This is antithetical to our nature, which is why depression is so rampant in society.

  10. It's not chemical!! You have a narcissist somewhere in your life!! Doctors and therapist have been lying to us for years. ALL the mental disorders come from neglect abuse or spoiling a child!! They have known this forever. But they just won't share it. It's just to profitable to get you addicted to their pills!

  11. They didn’t talk about the placebo effect. Some of these results could be from the fact that people believe that they’re going to be happier and healthier with their drugs. The mind is a powerful thing. It can make you depressed and then it can make you happy.

  12. This is completely unscientific and merely a personal anecdote, SSRIs didn't help my depression but surprisingly (or unsurprisingly) psychedelic drugs did. I felt significantly better after my first psylocibin trip as compared to years on Zoloft. Obviously, it depends on the person but I think hallucinogens in the future might be an accepted way to treat mental illness.

  13. I open YouTube to google the zoloft my doc just prescribed and THIS WAS THE FIRST VIDEO WHEN THE APP OPENED.

    I love you thank you for making this video

  14. It’s actually very interesting that there’s a correlation with the immune system. It makes a lot of sense because the immune system is about making yourself better (obviously) and I never thought about the emotional aspect of an immune system.

  15. Isn't it possible for a person to be depressed because their life actually sucks ? Or does a person have to be happy about life no matter how crappy their existence is , the fact that they're live is supposed to be reason enough to be happy all the damn time ? Why is it that society expects everyone to always be over joyed with life every waking moment ? Expecting such things is damaging to a person emotionally especially if that person doesn't have an ideal living situation .

  16. My mom keeps telling me I have control of my mood. I tell her I don't. So she punishes me. Because I have depression. Thanks

  17. According to the DSM I have depression. I guess I never knew what I've been feeling can be defined in such a way. I thought it'd have to be much more severe to actually be called depression.

  18. Ssri’s effects are acumulative, that’s why it takes weeks to start feeling a change. (6 weeks in my case)

  19. ive had depression for a year, and im 16. BUT, it has had a slight improvement recently. so i would have to geuss that by the time im 18 or so i should be better

  20. Hey look I have been diagnosed with manic depression and PTSD before cognitive memory. Please PLEASE PLEASE PLEASE HIT ME UP.

  21. It's not just a chemical imbalance.. a chemical imbalance will come from somewhere, saying "depression is just a chemical imbalance" is like saying a pressure wound (you seen on abused dogs who've worn their collar their whole life and its grown into their skin) is just a bit of blood and fixing that by cleaning the wound.. but they never bother removing the collar.

    to fix your depression you need to fix the cause.

  22. Ive had enough of depression, i have it long enough that im trying to find a way to make myself better

    I do one of the worst one, drinking

  23. Man, I’ve been on meds for depression for about 5 years now. I’ve tried all different brands and types (Zoloft, Prozac, Abilify, etc etc) and it just doesn’t work for me, no matter which one it is Guess I’m fucked 🤙

  24. Chronic Depression is draining. I began having it before I was a teen, now over half a century old, it still rears its ugly head occasionally. I have to be cautious about what I see, hear, read, and live, or else it takes me to a mental abyss. Some years ago, I had some Iboga- similar to Ayahuasca. It was a small dose, I did not lose my sense of reality and Iboga calmed that part of my brain down for several years.
    I need it again.
    C'est la vie…

  25. it sorta scares me that I have depression and doctors don't know 100% how to fix it but I'm still tryna hang on for y'all. also, to the teenagers faking it watching this video hoping to be diagnosed or something, that's not normal to WANT a mental illness. you guys don't know how hard it is for us. just because it's common doesn't mean it's not severe. it's one of the leading mental illnesses causing death among humans because ppl r so hopeless that they just want to die. all I'm saying to you is that you'll crash and fail. No one will end up liking you bc you faked mental illness. the whole school will end up finding out, and it won't end in ur favor. so, I'm just warning you now, stop.

  26. Why can't I get over my depression? It was 15 months ago and I'm still having episodes from time to time.

  27. theres also complications with other mental health problems, for example adhd has something to do with lack of dopamine, so when an adhd person is depressed it often has something to do with that.

  28. when people break up. they often say they are depressed. people should stop using that word.. you guys are sad not depressed. depression is a much much darker thing .

  29. I'm eighteen, and I've had depression since I was twelve. Thank you for this incredibly well-made and respectful video, it clears up a lot of myths I've had people assume were true for me.

  30. While I agree you don't need to know how a medicine works to know it works, you should have at least a basic knowledge of what it does and what the side effects can be.

  31. Thanks for the info. I've known many depressed people in my life, and I have even had episodes myself… Not as severe as the people around me
    Currently I have a friend who is essentially dead to the world right now…. 24 years old…. Out of work for almost a year now, due to lack of effort,… No degree… No ambition… Just plays video games or sleeps in his room in his parents house all day. Never eats…. If he does, it's very little, and crappy food.
    Can't even drink because two beers and he throws up… Idk if that's involved.
    Smokes weed from a pen all day.
    Smokes cigs in his room.
    His room is trashed. I've gone in there and seen mold in food sitting out.
    His friends and family have mostly just stopped communication w him… Even his best friend in the whole world… Because he just won't do anything.
    I don't stop being friends w him, although I barely see him, because I know he needs someone, but also he's a cool guy.
    He has gone on depression meds, although they obviously have not helped… And I think he gave them up because of that.
    He has confided in me that he feels numb… He feels literally nothing. Just no motivation to do anything.
    Any advice???

  32. My dad knows and fully stated that my depression is real but he still told me to get over it. Luckily he gone

  33. the best thing you can do to improve a depressed persons life is to… improve their life. You can't just medicate someone to be happy when they feel entirely alone and hopeless because that's their actual reality.

  34. Not liking how you treat depression (and a lot of other psychological issues/disorders) as if they all have some cause inside our brains and bodies. A lot of the time what's needed isn't medication but a change in the environment, a more compassionate society, room for diversity in how people exist and function. You need to be more broad in your tackling of this subject, and not blame biology (i.e. the individual) for being 'wrong'.

  35. There is hope on the horizon. That gives me hope. I have suffered depression since the age of 15 after an ATV accident that caused a frontal lobe injury. I am 47 now. I know mine is related to my TBI but it still hurts a lot. I do my best to get by but struggle daily in all aspects of my life. Work, family, relationships, everything. I just gotta keep on keeping on I tell myself but often times it gets overwhelming.

  36. I have dealt with depression since I was 8 years old and I am now 63. I have tried everything you can imagine but it is always there in the background. Even when I have good days I worry about when it’s going to rear it’s ugly head. But, I’ll be damned if I will ever give up because when I have good days life is worth all the inner turmoil of the bad ones.

  37. As a person with mental health issues pursuing higher education in the life sciences I can attest that mental health is easier to diagnose and treat than to research and explain scientifically.

  38. Chronic depressant here. For me when I'm having an episode, I am just straight up a zombie. I feel nothing but numbess and just want to sleep but yet can't fall asleep because my ADHD brain refuses to shut off. Then let's throw in anxiety too and it's one helluva bad episode. I've been off meds for over 10 years because of no insurance, and now begging my own mother to take me to see a doctor. But it never happens, then she has the gall to say I'm not trying to help myself. Sorry but I cannot walk that far to see a doctor and she's got the only keys to the jeep. Due to my mental problems I'm disabled so I'm pretty much isolated. But it's fine. I just keep on struggling and hoping soon to be out of here to live with a friend. At least my calico cat, Lucky, cares when I'm having an episode, she'll plaster herself on me and won't let go. My animals really are the only reason why I'm still living and getting up each day.

  39. Start by going to a gym and get on a diet. It worked for me! I feel normal again after 3 Months.
    Just clear your mind and focus on the workout.
    Say if you are jogging just focus on the task, if your lifiting weights think about your repetitions and do the same while doing your abbs.
    The total ammount of time this should take is about 3 hours and about the time you are done the first day you’ll feel 10 times better.
    Why? Mostly because the brain secretes endorphines and those hormones are feel good hormones that not only makes you have a better mood but also it numbs pain.

  40. Luckily I haven't been fully diagnosed with depression but am pretty close due to chronic pain. Luckily my medication is also antidepressant and boosted my mood noticeably to my family.

  41. There is a proven connection between depression and social media use. Ditch social media and become happier!

  42. I think that most things talked in this video are symptoms rather than the cause. Depression is so common because our lifestyle has changed. Despite being connected more than ever through the internet with the rest of the world, we have fewer friends and people than we can count on in the case of an emergency. Moreover, the expectations for us are higher than ever before, because we live in such convenient and almost sci-fi world. With all these improvements in technology and opportunities that are supposedly at every corner(but ofc it's not true, but previous generations see this in that way and they of course never cease to remind us about it), everybody feels like they should be popular, rich, talented, etc. We look at social media and we see that our friends are better at this game of life than us and we feel miserable because we are unable to live up to such standards. We often forget that what people shows on fb are the best parts of their life, when the worst are never publicized. And so on… I could go on but this post is too long anyway.

  43. Any researchers know how mathematicians can help out in this field? I’m hoping to pursue a math degree since that is what I’m most interested in and enjoy, but God does this seem interesting.

  44. You really focused on the neurobiological aspects of both the pathophysiology and the treatment of depression. Based on the title I hoped for a more balanced view. For example, statistically psychotherapy and pharmacotherapy are equally successful in treating depression (even though a single patient might react only to one of both treatments). And adverse childhood events are harmful and often they become particularly harmful by interacting with genetic factors, but the current living conditions of somebody is also a strong factor. You should also discuss causation and correlation when describing studies about changes in the brain in people with depression.

  45. I think that it is normal to feel sad / depressed. Events in our lives which seem beyond our control happen. Examine the root cause and try to restructure your life.

  46. I thought i had depression until i realized that i just dont like myself. Sometimes you meet someone you dont like because of their personality. Well in this case, it might be yourself. Ive learned to tollerate what i cant change. Others have true depression and i wish them the best.

  47. SSRI ruined my life!! Do not try SSRI!! Try adderall instead, it saved my life. I just saved countless lives, your welcome.

  48. I've had adhd and depression my whole life. Best thing to do is just to lower your expectations of yourself.

  49. My depression wouldn't leave me so you wanna know what i did ? I started dating it . It left me two days later😁😂😂🤷

  50. If thrs hope on the horizon and things does not go well for me this month I'm calling it a day on my life tho

  51. Isolation and low self-esteem make it real hard too. Amplifies the feeling of low motivation for myself.

  52. Patient: My life sucks, I want to kill myself. My girlfriend left me for another guy after cheating on me with him, my family hates me, and I lost my job.

    Doctor: Well you're obviously depressed because of a chemical imbalance! Let's issue you expensive meds!

  53. Depression has everything to do with Chemical Imbalance. @3:45 I need a citation. My understand is the humans do not grow new neurons. Gray matter sure but not new neurons have been found. https://www.scientificamerican.com/article/does-the-adult-brain-really-grow-new-neurons/

  54. This video is the best answer to people who tell us to "just get over it". Because it doesn't talk about will. It talks about multiple purely mechanical ways some bodies are just more fit for depression. Ways over which willpower is clearly not enough (tho still necessary, of course^^), if even relevant.

  55. Huge link with anxiety. Fighting anxiety all your waking hours is like being walked to the gallows everyday for decades. The cumulative effect makes you shut down and recoil from everyone and everything.

    You wake up alone feeling like a cork floating in the middle of the ocean with no direction, no hopes, no dreams, no one to even talk to.

    Fear from every direction ends in crushing loneliness and depression. You reach out are told "You made your choice".

    No one chooses to cry alone everyday of their life. We all a subject to a pity party now and then but no one wants to make it a lifestyle. People pull away and call you "a negative energy". They say they can't live like this as if it is someone's choice to just go on in the hopes something might change.

  56. So many people here having such shallow takes, talking about how other people not taking it seriously or what have you. The title is telling you that a factor in your life or a fundemental block, value or event, is causing all this strife and sadness. This should be a moment of deep introspection for anyone who‘s life is being ruined by depression. I‘m going to take a wild guess that most people here, likely teenagers, haven‘t gone through extensive psychoanalysis.

  57. Does that mean depression is only neurological? Because I mean, yeah, antidepressants may make you feel better, but I've never really seen anyone been cured by them.
    They are only complementary. It always takes psychological treatment with a therapist to really work (and, even that may not take anywhere). Mind doesn't exactly mean brain… or am I wrong? (serious question)

  58. How about loss of motivation, lack of direction, inability to move forward, negativity????? It can also be a lifelong issue that NEVER actually heals all one can do is manage it. drugs just dull it all down and maybe smooth the swings and have their own pitfalls.. One thing for sure an Academic is totally the incorrect type to actually understand Depression. Its more relate able to an artistic person. Personal interests/ hobies are the strongest antidepressants with the most meaning and impct followed by at least minor interaction with a friend or friendly group. Outdoors expecially nature is a solid forum to overcome Depressions and its impact asnd exersize (the least likely to be sought does certainly help with symptoms).

  59. Biggest issue is everyone including Doctors think Depression is something "you have to get over" They dont really want to see it as anything but a label.

  60. There is no such thing as a chemical imbalance, except for the one that is caused by psychotropic drugs.  So says Dr. Peter Breggin.

  61. Triggering events has caused my depression. I’ve been going through a non stop depression since July 2018. I honestly can’t remember the last time I was genuinely happy about life and worry free. I also have bad anxiety sometimes… I just want to be happy again

  62. The DSM – where symptom picture overlap and lack of bio markers make it read like a choose your own adventure.

Leave a Reply

Your email address will not be published. Required fields are marked *