Is depression an infectious disease? | Turhan Canli | TEDxSBU

Thank You Nancy for the sweet introduction thank you to all of you for sticking around it's been a pretty amazing day and so thanks for being here when I was younger personal conversations with my friends tended to revolve around our personal aspirations and dreams what schools we were going to apply to what kinds of jobs were hoping to get now that we're all a little older they tend to revolve around the welfare of our aging parents one of my friends has a mother who lives in India lately she started losing weight she was complaining about poor sleep and she was losing interest in things that she used to enjoy this pretty much sums up many of the symptoms of major depression and as a matter of fact when she was placed on antidepressants her condition improved but you know what she did not consider her illness to be emotional in nature she thought of it as a physical thing the emotional part it was there but it didn't occur to her to connect it to her condition she didn't connect the dots and here's the thing perhaps she's right perhaps major depression is not primarily an emotional disorder now that kind of statement is quite a departure from the status quo because for the last 60 years we have worked on the assumption that it is an emotional disorder one that is tied to the brain and in the process we have made progress we discovered that major depression is associated with imbalances in neurotransmitters we've identified brain regions that are associated with depression and the structural changes that go with it and we develop medications intended to address these symptoms do they work well that depends how you want to define success there's no question that antidepressants are very popular we consume a ton of medication the Centers for Disease Control reported that in the period between 2005 and 2008 one in 10 individuals over the age of 12 was on antidepressants that number is likely to be hired today and in fact in severe cases of depression these drugs do provide relief but critics have argued that for less severe cases of depression these antidepressants are barely better than sugar pills and regardless they do not cure depression once you've had your first episode of major depression there's a 50% chance that you will have another if you do there's an 80% chance you're going to have a third so why is that it's because we do not understand the underlying mechanisms that lead to these imbalances in neurotransmitters that lead to these structural changes and so we're stumbling in the dark in clinical practice we rely on trial and error if you go to the doctor's office you would get a prescription and if it works great no questions asked everybody's happy if it doesn't work what happens you up the dose you switch medications and you keep doing that until you find something that works eventually so that is the state-of-the-art after 60 years of research so I'm suggesting a different approach I'm suggesting to we conceptualize major depression as some form of infectious disease now you may go what but consider what is self-evident – my friend's mother patients who are depressed act as if they are sick are they're lethargic they lose appetite they lose interest they may have a tough time even getting out of bed and it turns out that depression is indeed associated with biomarkers of inflammation a signal of some kind of illness and so researchers have begun to consider the possibility that inflammation may indeed cause or significantly contribute to depression but then I have to ask what is the cause of the inflammation in the first place it could be the activation of an immune response response to an infection which could come from parasites bacteria or viruses now is there any evidence at all in nature that such microorganisms could change and alter their hosts behavior absolutely and I will give you a couple of examples as illustrations I don't mean to imply that the illustrations I'll give you are the cause of depression but they Ellis trait some of the mechanisms that Mother Nature has already figured out by which the infected hosts life and behavior can be altered and then I will take this new way of looking at depression and explain to you how it informs and changes our way of thinking about the genetics of depression which also has kind of run into a wall and then I will close with what I hope will be a call to arms so let me start with parasites let me start with the example the story of the suicidal cricket when a cricket becomes infected with a Gordian worm that worm grows inside of it until it reaches sexual maturity the problem for the worm is it can only mate in water and the cricket isn't a water creature so what do you think happens the cricket has its brain hijacked by the worm alters its behavior seeks out water and jumps into it in the process the cricket drowns and the worm emerges from the vessel it was in looking to get laid now researchers have begun to look into the biochemistry of this remarkable behavioral phenomenon and what they discovered is amazing they discovered that the worm dispenses proteins into the crickets head and when they look at the nature of these proteins they realize these are proteins that are already understood to affect neurotransmission and brain development let me give you another example this is the example of Toxoplasma gondii eye or talk so for short talk so only mates inside the intestines of cats and then it releases its eggs and the eggs I excreted through feline feces into the environment but talk so now has a problem how does the next generation of its you know how does its offspring make it into another cat right it wants its offspring to get into another cat so it can grow happily ever after and mate again always comes back to sex doesn't it so what does it do well it figured out an ingenious method for moving its eggs into another cat and it does so by infected rats that come into contact with feline feces or with the with the eggs that are around the environment and when a rat becomes infected with talk so it becomes sexually aroused and attracted to the scent of cat urine hey I'm not judging I'm just telling you okay so how does it do that it rewires the brain regions that are involved in fear processing and sexual arousal and it alters the levels of neurotransmitters in the rat's brain now the aroused rat instead of finding love strikes out big time gets eaten right and the stalks so inside the rat well it just found a new home and you thought your last move was a nightmare so humans can also become infected by toxin and as a matter of fact the numbers are staggering the estimates are that one third of the world's population and one fifth of the US population is infected with talk so one study was an epidemiological study of 20 European nations and what they were doing was correlating the prevalence of toxo presence with suicide rates and they found a significant positive correlation between the two I'm referring obviously to human suicides not cricket suicides or rat suicides all right so let me switch from parasites to bacteria as a second example did you know that we have more than a thousand species of bacteria living inside our guts we actually need them because they help us process the foods we ingest but they also seem to play a role in our emotional well-being researchers have begun to look at mice to do some animal studies to get at the underlying mechanisms and these were mice that were specifically engineered to be free of any intestinal bacteria so we're talking germ-free mice would you love to have those in your dorm room right now these mice are easily stressed when subjected to psychological stressors in the lab but their stress response can become normalized when they are treated with common intestinal bacterial strains and there's also a number of studies in humans that have begun to look at the role of probiotics these you know healthy bacterial colonies and reported that you know research participants reported improvement in their mood and reduction in anxious and depressive symptoms and one brain imaging study reported that over the course of a four week diet probiotic diet brain activation patterns changed significantly in these participants so now if bacteria can lift your mood maybe there's others that can depress it or maybe sometimes in some people these good bacteria could mutate and basically become emotional pathogens and maybe there's a difference between the intestinal bacterial composition of a healthy person compared to that of a depressed person if that were the case then maybe transferring the bacterial content of a healthy person and transplanting it into a depressed person might constitute some form of therapy so I'm talking about fecal transplants gross right but it's actually been done not in depressed patients it's been done in some cases of really difficult to treat diarrhea and they'd worked really well so you know next time you see a depressed person they tell you our shitty they feel you know maybe there's something to it let me turn to let me turn to viruses viruses are the most ubiquitous life-form on earth they have many ways to invade our bodies they can stay dormant for a long time until they are activated by some sort of external event perhaps a stressful life event and they can be passed across generations these are all things that are consistent with what we know about depression I'll give you one example here the Boerner disease virus or BDD it infects farm animals and causes neurological symptoms in these animals according to one study can also infect the human brain and the likelihood in fact of infection is great and depressed individuals than it is in non depressed individuals there was one very small clinical study that found that depressed patients who happen to be infected with Borna when they were treated for the for the virus not only experienced reduction in the biomarkers for the virus but also reported improvement in depressive symptoms at the same time this is a very controversial field because there's many studies that failed to find any link between bdv and depression at all but there's many other viruses to look at and when you start thinking about the role that these microorganisms can play you start thinking about the genetics of depression twins study suggests that there should be genes that play a role in depression but when we look for them we have a tough time finding them why is that well maybe we're looking at the wrong organism maybe we should be looking at the genomes of all of these microorganisms that we carry with us and you know the work sofas looked at the human genome but you know what it's not all human our genome isn't all human both parasites and viruses can insert their genetic material into ours in fact 8% of our DNA is believed to come from these alien sources and that bdv virus I talked about before it was recently discovered that segments of its DNA are in ours so maybe the genes associated oppresion lurk in these genomes of all of these microorganisms we carry in us or maybe they lurk in spaces we haven't looked at before like these you know foreign elements of DNA that are embedded in ours so this is my thesis that major depression could be a form of an infectious disease which could be caused by parasitic bacterial or viral sources that could go undetected until activated by some event that once activated has the power and the mechanisms to alter our neurotransmission and rewire our brains and that can be passed around from generation to generation which could be the missing genetic piece that eluded us so far now I can almost see the collective worry over this crowd going um I have this roommate he's been bummed out lately am I going to catch depression from him I don't think so if that were the case then 100 percent of the population would happen and that's not the case all right so an infectious disease does not necessarily mean it's a contagious disease so we can all have a communal sign of relief we won't catch anything that way all right but by reconceptualizing depression as infectious disease we have a new approach to think about mechanisms and genetic targets so this is my call to arms let's not settle for symptom reduction let's commit ourselves to finding a genuine you or let's aspire to that let us do that so that hopelessness so much a feature of depression may give way to hope after all and in the language of my friend's mother Shakya thank you


  1. I have been researching depression and autoimmune diseases for the past 2.5 years and this guy is spot on. He asks the most important question that medical doctors are not taught to ask. WHY?

    Most conversations go like this:

    You aren't feeling well:
    Doctor: "You are depressed it is caused by low serotonin"
    You ask "ok but why is it low, what caused it?"
    The doctors answer: "we really don't know, there is an aspect of it being hereditary and stress related, but we can give you medicine for the depression"

    Then it stops there, when in fact the doctor should ask about infections or travel history to areas with epidemics and then possibly prophylactically treat that possible underlying illness. If doctors fail to do this they are endangering their patients who would have a disease eating them alive as their depressive symptoms are treated.

  2. I have fought with depression since my divorce three years ago. an actual low point when I received this depression treatment “fetching kafon press” (Google it) and my self-confidence was smashed. Within weeks of reading your book and putting your advice into practice, my depression had completely lifted and my self-confidence began to return..

  3. I absolutly believe depression could be caused by an immuunreaction. I have lyme disease and since that moment my mind changed. I don't like to do anything, even while it's still possible for my body. It's a fight to do something, when i should just listen to my mind i should just lay down the whole day.

  4. What you are describing here is a physical depression and the only reason we see it as depression because some of the symptom are similar to depression, the truth is that there is a virus internally that the body has been fighting for quite some time and not winning, then the mind takes over and the first thing it dose reduce the overall power to half forcing you to lay down which is the number one step to combat viruses, This Idea that depression can be a form of fighting mechanism is very true, consider this "" did panic disorder provided a form of protection to our ancestors at a time when anti medicine was not available"" the answer is yes. There are 2 states in depression, a natural depression and a physical depression, you should always check for those two condition before you proceed to correct it, please continue your research on these line as I am sure it will help people to identify what state they are in intern reducing the inability to recover from depression.
    Excellent video, good luck

  5. This is too big an extrapolation from a limited viewpoint. I won't rule out the possibility that infection may be a factor, however, replacing one too-simple explanation with another only serves to confuse the issue not illuminate it.

    Since depression is strongly influenced by exercise, it can also be called a sedentary lifestyle disease. Since it is strongly influenced by social ties and regular connection, it can be called a social disease. Since depression can be caused by grief, it can be called a disease of loss. Since depression can often be treated by CBT it can be called a cognitive skill disease. Since depression is lower among regular meditators or people of strong faith (not just Christian) it can be called a lack of faith.
    Since depression can sometimes be cured with electro-shock or or strong magnetic fields, perhaps depression is an electro-magnetic disease. Since sometimes it can be successfully treated with SSRIs it may sometimes, or often, actually be a serotonin deficiency.

    Even given that inflammation is a cause of depression, since inflammation can be caused by allergies, depression can be called an allergy. Since inflammation can be caused by diet and obesity, depression can also be called an eating disorder. Since meat, eggs and dairy are all pro-inflammatory, perhaps depression is the revenge of the animals. Should I go on?

  6. I've been taking turmeric as an anti-inflammatory agent, which worked great for me.
    An added bonus has been my elevated moods.
    Just my experience…

  7. The neurotransmitter hypothesis was formed on a faulty basis: that the drug Reserpine depletes serotonin/dopamine/norepinephrine and causes depression, therefore that depletion was the CAUSE of depression. But Reserpine doesn't always cause depression even though it depletes these chemicals. Sometimes it BOOSTS mood. If depression is caused by reduced neurotransmitters, that would not be possible. But psychiatry is too invested in this hypothesis to try other avenues, which is to the detriment of the patient.

  8. Eat whole, clean, very MINIMALLY processed foods with no "cheat days" for at least 6-7 months straight. Your gut bacteria population will slowly shift and you will start to notice your depression, energy levels and etc. change for the better or your depression and anxiety even get cured. By the way, sugar, bread, pasta, wheat and etc are all SUPER PROCESSED foods. Ruining people's gut flora!!

  9. When I was a child we all knew you can't catch cancer but it did run in families. Today some people understand the role of HPV and I am sure other virus strains will be found. Suicide is a greater cause of death in some age groups than is cancer. If there is a pathogens causing or assisting transmission of mood disorders it's important to investigate this avenue. Once upon a time we knew ulcers were a product of mood (stress) then the bacteria responsible was identified. Science has more to learn.

  10. I Confirm this INFO 100% by personal experience. Three heavy bacterial infections throughout my life, all three paired with distinct forms of "depression". All three times instinctively I knew that once i could clear the infection my brain chemicals would go back to normal. All three times I managed to achieve just that. (one of them was Lyme disease). "Antibiotics" (preferably natural ones) would empty mental institutions by 80%-90% in a matter of weeks. .. just my 2c.

  11. This may be the case for some people, but I was diagnosed with chronic depression 5 years ago but I am otherwise completely healthy. While these discoveries may hold water, we can't completely brush the psychological and chemical aspects under the rug in favor of this new "cure". Renaming depression an "infectious disease" instead of an emotional disorder or a chemical imbalance is only trading one negative stigma for another. Depression is not "infectious".

  12. absolutley..I e been studied my ups and downs after eating after a drink or a smoke and over the last 20 years plus including diagnosed With BP and 1500 mg SEROQUEL they tested me…Today 50 seroquel and a better Dr as I have earned my studies as the Patient.. …time if your depressed or not feeling good time..3 hrs = from the beginning to the end then gain your strength over the period of a day when your words are unheard..SL.ave

  13. I had him as a professor for neuroethology. Very challenging course, taught really well. One of the best in the field.

  14. I was depressed and had anxiety and sleeping problems, and I believe he is right. I cured my depression and anxiety. Is there any way to contact him and tell him how I did it?

  15. With what all my son and I have been exposed too and it's hard to get anyone to help really give us treatment is depressing

  16. >>Win control over your depression and finally gain the upper hand over all your depression symptoms.Destroy Depression

  17. That's an awesome presentation. As someone who has had depression drug resistant depression for many years….I am encouraged to see finally another approach to it. Thank you Turhan Canil. If you need a Guini pig

  18. depression is going to be the 3rd biggest in disability in the world, next to heart disease and diabetes. Yet all of us go through it at one point. -_- depression is very very bad, when it becomes a disorder, and it's getting harder to treat for some reason 

  19. Hmmm. VERY interesting. 

    Here's another "connect the dots" observation. 

    Because inhaling toxic wood smoke can cause physical inflammation, could inhaling wood smoke be a cause of the physical disease called depression?   

  20. Negative symptoms are a reflection of our lack of realization that bacteria and viruses are just ingredients to make change in our lives through our intention. ALL creatures have a purpose. Put them to work for you instead of contracting into fear.

  21. He makes some interesting points but he is also trying to boost the credibility of his case by misrepresenting results of other work. He makes the claim that we have sought genes that cause depression and haven't found many. That isn't true. Genome wide association studies (GWAs) have identified many genes of small effect. Plus the much vaunted GWA studies only look at a very small portion of the human genome.

    Most people with depression do not exhibit high levels of inflammatory (pro-inflammatory) biomarkers. There is a large subset of depressed patients that do exhibit high levels of said biomarkers. These biomarkers include pro-inflammatory cytokines such as Interleukin-6 (IL-6), Interferon, & Tumour Necrosis Factor (TMF). There are many others.

    Most people with depression present with hyperactivated HPA-axis functions. Their endocrine system produces too much cortisol a hormone associated with the fight or flight response such that they experience a chronic physiological stress response. These people experience a lot of anxiety. Indeed it is likely that exposure to too much stress over time will switch on the stress response such that it no longer switches off. Stress results in the production of cortisol by the adrenal glands. There are receptors that cortisol docks with. These receptors are called gluccocorticoid receptors. Once activated by exposure to cortisol they send a message back to the brain ordering it to stop making cortisol: "enough already, the threat is passed".

    Exposure to great stress as a child or prolonged stress as an adult leads the body to reduce production of these gluccocorticoid receptors so the feed back mechanism stops working properly. The stress response does not shut down when it should. People experience a physiological stress response that is greater than is appropriate. They start experiencing increasing levels of anxiety. The stress of daily living can become overwhelming. People resort to medication in order to cope. In some cases this simply allows the problem to get worse until the drugs can no longer manage the situation and people break down.

    The process that turns off the production of gluccocorticoid receptors is an epigenetic one. Enzymes place a permanent block on the genes coding for gluccocorticoid receptors. Once the block is placed these genes are switched off. Epigenetics is a relatively new field, one that has emerged as our understanding of genetics has improved. Our knowledge is growing exponentially.

    Indeed if you do not understand the rudiments of epigenetics you cannot really come to understand the genetics of mental illness.

    To be clear, an epigenetic change is roughly equivalent to a true genetic change. That means that real life events, especially traumatic ones have a permanent genetic effect.

    When this fellow claims that we have looked for genes that cause depression and didn't find any or many, he is either being deliberately misleading or simply does not understand the important contribution of genetics to mental illness. One need not have any "risk" genes (genes that increase the risk that you will eventually develop depression) in order to experience depression that is inherently genetic. A traumatic life event leads to a permanent genetic change that leads to a life time of chronic stress.

    The brains of people who have committed suicide exhibit massive epigenetic suppression of genes coding for gluccocorticoid receptors.

    I am not trying to make the case for the genetic origins of depression. I am not saying the speaker is wrong and the geneticists are right. I am simply trying to make the case that he is overselling his theory.

    People with Hep. C infections have been treated with interferon for many years. Interferon is a pro-inflammatory cytokine. In many, if not most, cases patients are plunged into depression which lifts when the treatment ends.

    My mental illness emerged within a few hours of receiving a typhoid vaccination.

    Today scientists can take a skin cell from a patient and turn it into a stem cell from which nerves (neurons) can be grown. These scientists can then study your neurons without harming you. One of the typical experiments is to induce inflammation in these nerve cells to study their response. One of the ways of inducing inflammation is to apply a vaccine. The Typhoid vaccine is very potent and generates a rapid immune response. Inflammation is part of the immense response.

    There are many factors contributing to the depression epidemic it is fast becoming the greatest cause of disability in the world it is almost certainly multifactorial. Infection may well be one factor or one cause.

    It would be imprudent (the scientific term for foolish) to presume that infection is the major cause of depression. It would also be foolish to presume that some depression is NOT caused by infection or "infectious agents".

    I am simply troubled by this fellows attempts to discount the evidence that conflicts with his theory hoping the audience is not well enough informed to realize his use of misinformation to support his thesis.

    He doesn't need to. He should be making the case that some depression may be caused by infection. As for Toxoplasma gondii, the research community has been studying it for some time.

  22. This is entirely weird. First of all, inflammation is not synonymous to infection. Even if you proved depression is caused by inflammation, that still doesn't mean it's an infection. Then, it is clear that we can have psychiatric conditions due to lack of oxygen, or due to psychoactive drugs, or hormonal factors, that have nothing to do with inflammation and/or infection. Therefore, it is impossible that all "depressions" are inflammation and/or infection, and it also makes it impossible that cytokines are the most important factor in developing depression. 

  23. Great talk!  Thank you for sharing this with the world.  Doctors really, really need to look at more pathological causes for some illnesses, especially ones like depression, anxiety, and unsolved mysteries like Fibromyalgia, Chronic Fatigue, M/E.   I am doing so much better with treatment to get the mold toxins out of my system.  I have a long ways to go, but I am starting to feel like I'm getting my brain back.   This article helped me talk to doctors about it.

  24. Must be a record for the most uses of the qualifier "maybe". One big red flag in this talk is when he highlights the suggestive findings of a very small study (his description) of BVD virus and depression even though the vast majority of other studies show nothing of interest.  Due to their sensitivity to statistical randomness, in the land of clinical trials you could find a small study to support anything you like.

  25. What you eat will change the balance and and proportions of bacteria in your gut. Eat poorly and you get more bad bacteria. Eat lots of veggies and you get better bacteria. The bad are probably still there, just not dominating the system.

  26. A diet rich in trans fats and sugar has been shown to promote inflammation, while a healthy one full of fruit, veg and oily fish helps keep it at bay. Obesity is another risk factor, probably because body fat, particularly around the belly, stores large quantities of cytokines.

  27. This is really interesting thank you. The link between depression and infection will continue to be substantiated, I am certain. There is already reseach developing between the disciplines of psychology, neurology and immunology. 
    There is a really interesting book written some time ago, called the 'molecules of emotion' by candice pert, who researched the mind body connection, Psycho Neuro Immunology (PNI ) research is helping to open up the debate about how stress changes the physiology, (cortisol suppresses the immune response  and is always high in chronic stress)  brilliant TED talk thanks 

  28. Very interesting hypothesis- it has been clearly demonstrated that stress and low mood have negative effects on the immune system, so pathogens that would normally be suppressed when someone is emotionally healthy could begin to multiply and cause damaging infections when someone is subject to extreme stress, further weakening them and reducing their resilience. It makes sense that this diminished resilience would amplify the effect of any stressors an individual is undergoing, potentially leading to the loss of the ability to cope with daily life, which is one of the main symptoms of major depression.

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