Anorexia Isn’t Just a Psychiatric Disorder

[♪ INTRO] Anorexia nervosa is a common and dangerous
illness that affects millions of people. For a long time, it’s been thought of primarily
as a psychiatric disorder, but new research published this week in the
journal Nature Genetics suggests there’s an important physiological
aspect as well. This research links the disorder to genetics
and metabolism, and it might change the way we understand
the origins of the illness as well as potential treatments. Anorexia nervosa is an eating disorder. Affected people may be dangerously underweight, with a restricted intake of food, and often also have a distorted body image. The end result is that the body is starved
of sufficient nutrients, which can lead to various medical complications
and even death. In fact, according to the U.S. National Institute
of Mental Health, anorexia is the most deadly mental disorder. Even with treatment, many patients struggle
to fully overcome anorexia. The authors of this new research suggest that
current treatments might be too focused on psychology, and fail to consider the physiology involved
in the disorder. This study pulled together genetic data on
almost 17,000 cases of anorexia nervosa among people
of European ancestry. When they compared that dataset with a control
group, they found 8 genetic variants significantly
associated with anorexia. Interestingly, some of these genetic traits
are also known to be related to levels of physical activity,
as well as to metabolism, the processes inside the body that convert
sustenance into energy. People suffering from anorexia have been known
to show signs of abnormal metabolism, but this has often
been thought of as a side effect of being starved of nutrients. However, the researchers say this genetic
link means that an unusual metabolism might actually
be partly responsible for causing the disorder. The researchers say we should think of anorexia
nervosa as arising from a combination of both psychological
and physiological factors. They say their analysis potentially expands
the list of risk factors for the disorder — that is, characteristics
that increase a person’s likelihood of developing it. And that in turn opens up a whole new avenue
for medical professionals looking to develop treatments for this deadly
disease. And anorexia isn’t the only illness that’s
more complicated than it seems. Another new study this week, published in the Journal of the American Medical Association, found a similar duality with dementia — but
the other way around. Dementia is defined as a decline in mental
ability that’s severe enough to interfere with a
person’s daily life. It can take many forms, but the most common
is Alzheimer’s disease, which affects more than five million people
in the US alone. And Alzheimer’s is known to be linked to
genes. There are well-known genetic risk factors
that are associated with a patient’s likelihood of
developing Alzheimer’s. But this new study found that dementia can
also be influenced by how healthy a person’s lifestyle
is. Like the first study, this one looked at a
wide sample of genetic data, this time from nearly 200,000 people in the
UK, including more than 1700 recorded cases of
dementia. The researchers assembled a genetic risk score
for each person, but also a lifestyle health score based on
each person’s self-reported diet, level of physical activity, and frequency
of smoking or drinking alcohol. They found that, even among people with a
high genetic risk, the incidence of dementia was significantly
lower in people with a healthier lifestyle versus people living less
healthy. The difference was small but noteworthy. Of the study participants with high genetic
risk of dementia, the disease developed in 1.78% of those with
unhealthy habits, but only 1.13% of those with a healthier lifestyle. In absolute terms, this would mean that if
people at high genetic risk improved their lifestyle, one case of dementia
could be prevented for each 121 at-risk individuals every decade. So this is certainly not a cure, but it does
seem that dementia, like anorexia nervosa, is related to a combination
of factors, both genetic and behavioral. Which is exciting because as we learn more, we might discover ways for people to offset
their built-in risk of dementia by adjusting their behavior and
lifestyle. But there’s definitely still more to be
learned. Both of these studies looked at specific populations
of people, mainly those of European ancestry. And it will no doubt take more study in more
diverse populations to tease out exact interrelationships between
the various factors involved in these diseases. But the takeaway here is that illness is complicated
– especially the ones we haven’t figured out
how to treat yet. Genetics can be very helpful in understanding
where diseases arise, but your genes are not your destiny. Diseases often have complex and interrelated
causes, and the more we come to understand that complexity, the better chance we have in the fight against
them. Thanks for watching this episode of SciShow
News. If you’re interested in helping us bring
great videos to the world every day, from news to quick questions to deep dives,
you can support us on Patreon. Check it out – – that’s
the whole reason we can do this. Thanks everybody. [♪ OUTRO]

100 thoughts on “Anorexia Isn’t Just a Psychiatric Disorder

  1. I have someone in my family with anorexia as well as someone with dementia. And yeah. This stuff is complex.

  2. I wonder if that new insight into the genetics of anorexia could potentially help develop treatments for obesity

  3. You would think all the previous generations that carry this disorder would of starved to death and it wouldn't still be passed on.

  4. Autism and eating disorders often go hand in hand. I wouldn't be surprised if they were linked with some of the same genetics.

  5. Many US citizens now at physical exam: Oh, so I can be someone potentially affected by anorexia, so doctor , keeping my 300 pounds is actually a lifestyle that protects me. So farewell these diets and exercises you are enforcing me, I won't be a candidate for anorexia. Bye…

  6. Hey! I was wondering, how do you get access to science journals as a young lad? Looking forward to reading them but I do not know how to get ahold of them. I also can't afford Deepdyve.

  7. I have some questions maybe someone can help me answer. I read some of the sources in the description, but couldn't find an answer.

    I was under the impression that genes can be "turned on" and "turned off" in response to certain conditions the body is in (learned this in the veritasium video about anti-dandruff shampoo). So my question is: how do we know that these genetic associations with anorexia are really part of the cause and not just a response of the body to anorexia?

    From the articles in the description I could not get an answer for this. They stated that they compared people who already have Anorexia Nervosa (defined by another source from the description as already showing symptoms of weight-loss or fail to gain weight when they are supposed to) to people who don't. In order to confirm that the genes are responsible, I would imagine they should also test people who recovered from anorexia to see if the genetic markers are still present. Else this could still just be an association, but not a causation.


  8. Then again what psychiatric disorder doesn't involve problems with metabolism related genes in neurons? Hmmm?

  9. Sometimes your genes are your destiny. My friends husband has Huntington’s, which is ALL about the genes.

  10. Hi scishow
    Learned some insight into anorexia and dementia.Role of genetics in this disease..
    Thanks scishow i can't miss your daily episodes..???

  11. DNA is stupid specific, its molecules wide and 2M LONG!!! Just think about that and how often your body does it. What was I talking about? Oh yea, so 8 genes out of 100,000+ that we only had 24,000, 6 years ago.

  12. Daily reminder that we call anorexia and dementia illnesses but gender dysphoria is "absolutely normal" because it only requires heavy surgery, heavy use of medication and psychiatric treatment.

  13. Karen Carpenter RIP….

    They should also check out the Dopamine Reward System for a connection to anorexia.

  14. The general disclaimer was not enough in this. I'm generally for SciShows attempts at outlandish theory because it usually doesn't affect people, but here it does. The risk of developing alzeimhers based on active, healthy lifestyle was almost identical statistically, and those genetic markers for metabolism make explain everything or nothing, nor provide adequate detail on treatments that could target specific metabolic or diet changes that would reinforce the hypothesis. This is PopSci news, not SciShow news, and I've learned to expect more from SciShow

  15. Has anyone conducted research to obtain the percentage of populations who have anorexia and dementia among tribal peoples who live at the subsistence level?

  16. A friend of mine died last May from anorexia, after suffering for 8 years. Throughout all these years, she was continually shamed for her condition, both by her family and the staff of the hospital she was regularly admitted to. I feel like if they were a bit more understanding and didn't put so much pressure on her, she might have still been alive.

  17. Did y'all plan this with Shane or something because both came out exactly 11 hours ago and if not, this is the most strange coincidence..

  18. I really like episodes like this. It would be otherwise impossible to keep up to date on scientific discoveries.

  19. hey thanks for the sources. but could you maybe give a title to the sources. so i know which sources i need to click to get what? 🙂
    i was looking for the study on annorexia but the one source is just a general article about diagnosis it seems?

    love sci-show! greetings from the Netherlands!

  20. Question: if anorexia is now being shown as having a genetic and metabolic component, will there be less attacks (not by this community but in general) against people with obesity, as it can also have a genetic and metabolic component?

    Fat shaming is the last acceptable form of discrimination it seems, which can lead to death just like anorexia. But it has always seemed like people suffering with anorexia get more sympathy than people suffering with obesity.

    I do not want to take away from anyone's struggle. I simply would love people to treat all weight issues with compassion, rather than treating one with compassion and one with derision. Maybe then we all can find ways to be healthy instead of helping one side and shaming the other.

  21. Anyone suffering with an ED please be aware that this video could be triggering. I know some people find this new information a relief, but for me I am taking it very hard. I am in recovery from anorexia nervosa and am finding this triggering.

  22. what an incredible, groundbreaking find, for mental disorders to be affected by genetics? who woulve thunk! /sarcasm
    well, i suppose this might be unexpected for blank slate/evolution stops at the neck believers, also no, genetics is your destiny

  23. When Hank talks he looks like he's translating for deaf people that he's taught his own language of signing. I see it in all of the videos but extra in this one. Lol

  24. What does it mean to have healthy habits for those who could be at risk for dementia? What foods would help?

  25. “Your genes are not your destiny” – Hank Green
    “You can only fight your genes for so long. You must accept the inevitable.” – my doctor.
    The moral is, my doctor was right. Fighting my genes only bought me two painful hellish years. Accepting the inevitable brought me inner peace. Twenty-five years later, through acceptance, I finally healed the damage caused by those two years of trying to fight the inevitable (healthy diet and exercise were NOT the answer – just a band-aid).

  26. A study based on each persons self reported diet and level of physical activity etc is hardly scientific.
    Linking an eating disorder to genetics would probably endanger more lives than saving them. I can already see obese and body positivity moment types using this as food for the shape they are in.

  27. I still think we are in the absolute infancy of understanding any mental health problems. We will look back on this point in history and see ourselves as blind men splashing around in the dark. (Speaking as someone who has suffered for 30 years and had every treatment available with only the most minor or temporary effects).

  28. Excellent, excellent timing – I'm so impressed with whichever social media aware/youtube in-tune person made this decision – kudos to you!

  29. just tie them up and force feed for a couple of weeks with nutrient dense food. What an easy treatment.

  30. There is also research showing the impact of omega 3 and b vitamins on mental health. They have also found that pro inflammatory diets can trigger depression. This is why diet in mental health treatment should be included in the treatment plan with equal importance. It's not all about weight gain through any means, it should be about healthy weight gain consuming foods that promote good mental health

  31. What did the difference look like, what was the power of the significance. Big Data can make anything look significant, but the power behind that significance is more important than the significance by itself. Significance plus low-power equals useless result. Genes, in any case have never been shown to reliably code for any behaviour in humans. Even the "most genetic psychiatric disorders" liks schizophrenia only occur by chance given one twin is diagnosed in a twin study (50% is chance…just sayin).

    These kinds of studies attempting to relate behaviour to gene encoding are a yellow brick road to normativity hiding as the wizard of enlightenment. Genes code for RNA (FULL STOP). There are way to many steps between Genes and cognition to be able to reduce any behaviour to any variant, in addition there is little evidence to support the thesis that such eating conditions were prevalent anywhere before magazines like GQ and a vast supply of evidence that shows it to be culture-bound with mass-media exposure. That said, probably all psychiatric characterisations should be considered culter-bound.

    Whoever is crunching your numbers and looking at this stuff with a critical eye is doing a generally ok job, but they arre behind the times with some of psychiatry BS. This study is so 90s…

  32. In my psych classes nearly a decade ago, it was understood that basically every major mental illness is caused by an interaction between genes and environment (including behavioral factors). Was the medical field not in agreement?

  33. Really struggling with my recovery at the moment, seeing this pop up in my subscriptions reminded me how bad it would be to relapse

  34. I was part of the ANGI genetics study on which this research was partially based! Thank you for addressing such an important topic.

  35. I think this is more of bacterial, not psychological, psychological is a manifestation of behavior caused by bacteria

  36. How closely are anorexia and bulemia related? Like I know how the symptoms differ, but is bulemia considered a subtype of anorexia or…?

  37. You have to pray for them that have eating disorder. Pray for their salvation. You can lay your hands upon them and say, "Be born again in Jesus' name." It should help.

  38. I like "diseases we haven't worked out how to treat yet" as opposed to "untreatable" or "incurable". Nice little positive spin there, thanks Hank(s) x

  39. How does one find out if they have anorexia?

    for decades now, i have had trouble maintaining a proper weight. No matter how much i eat, i am always at least 10 lbs underweight, if not more. I at first attributed this to a high metabolism, but sometimes find that implausible as i can go as much as 15-30lbs under weight. I do not believe that this is psychological, as i think i am underweight, but back to the intial question. How does one find out if they have it?

  40. I'm a bit skeptical
    Every time there's a study that tries to show that a psychiatric disease has a genetic basis.
    Another study or review comes out that shows the results are negligible.
    This has been going on with schizophrenia for decades.
    I'm not that these conditions don't have a genetic component, everything does to a degree.
    I'm just skeptical about how much the research is gonna hold up after examinations and in future replications.
    But then I'll need to see the data and methodology first.

  41. I’ve always thought there was also a metabolic part of anorexia but to undermine the psychological problems they have like thinking they eat too much, fear of food, or seeing their body improperly then…I’d say that’s underestimating the weight of the psychological part of it but I have also seen people who have had anorexia eat high amounts of food and their weight stay the same where others would gain so that’s always been a no brainer to me.

  42. Sounds like the Dementia results are totally meaningless … I assume statistically it means nothing at all ..

  43. That makes sense! Ive struggled with eating enough my whole life. I also have a family history of eds and before we knew that i was just crazy.

  44. So media has no effect on causing anorexia in teenagers? I find that very hard to believe. The media burns an imagine into our children's mind at "how" the perfect woman/man should look. They can never reach these goals because they're unobtainable by a mere human. Hence anorexia is born. If you remove all media anorexia will as a disease disappear along with it.

  45. I used to do in home computer repair in Naples and Marco Island FL. The vast majority of my clients were retired with many 80+. And in striking up conversations with them while running scans and such I found a very strong correlation about someone "being normal" and keeping physically active, socially active, mentally active, and spiritually active. By normal I mean they can carry on a normal conversation, remember past and recent events, get around ok, and have a minimal amount of achs. Sample size of about 300, mix of male/female married/unmarried with some only observations and others I politely asked why are they as capable as me yet many others their age arent. So get up and go see your friends at the church puzzle group lol.

  46. OR the factors that increase your likelihood of getting dementia can also affect your behaviour in a way that can make you live a less healthy lifestyle.

  47. Currently in tears. I have been trying to get help for the genetic factors of my anorexia for over a decade. I don't have the "proper" physiological symptoms and thus have never been able to receive treatment. I am working to take a dietary protocol I invented and used to heal my husband's Junior Idiopathic Arthritis and rework it to help with illness on a genetic level. Difficult to do, but not impossible. Thank you Hank and SciShow for this video.

  48. Could you elaborate on how the metabolism affects anorexia, is it with slower, faster or idk just confused

  49. I'd like to see scishow do a vid on the science behind trans people. It would be interesting and might clear up some misconceptions about the actual science if any that's behind them

  50. As a recovered Anorexic I must admit what he’s saying about a wonky metabolism very might well be why I became Anorexic to begin with. Prior to Anorexia I never felt hunger. In order to feel hunger I starved in order to eat…later on that habit just lead to not eating at all because being Anorexic is “easy” when hunger is naturally rarely felt. Now that I’m better I’m right back to when I was younger…I seldom feel hunger or the need to eat…even drink…there is like no on switch for me unless I’m famished.

  51. I think this stuff about anorexia is presumptive & a mess of effect /cause /effect…

    You need to either stop talking about health matters or bring up the standards of your health care related episodes drastically…

    I've said this before but if you keep this up, you are going to get yourself in legal hot water.

    It's not ok to provide flawed, misunderstood, confused, unprofessional, etc. health care advice to the public!


  52. Ehh, sometime go on an extended fast. There’s a buzz you’ll find after a few days. There might be a touch of addiction in there as well.

  53. My metabolics lecturer strongly believed that their is a metabolic link and he have witnessed several cases where patients with fructosemia were also anorexic. Once they cut fructose out of their diets their body weight increased. (might have been galactosemia)

  54. Just love your presentations. You annunciate and project nicely. In other words you don't put me to sleep. A true teacher.

  55. Genetics expression changes as we age. Anorexia and dementia are examples of negative feedback loops resulting in negative expression of genes.

  56. well, depression usually is the cause of everything. For example I could be the healthiest man on the planet since I'm vegan, non smoker, no kids, bicycle and fresh air …. but I am too depressed to actually feel good.
    If you're sad you're sad. Period.

  57. Great job, SciShow! Y'all keep up the good work. Extremely entertaining and knowledgeable.
    Thanks from Pt.Neches,Tx

  58. Hey thanks for presenting anorexia in a non-triggering way. I'm two years into treatment and I can't tell you how poorly some handle the subject. People often overlook how it is a serious physical/medical issue it is, and it really affects our lives and health. Thanks for taking the medical stuff seriously.

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