The word “disease” is weirdly hard to define. You’ve got the common cold. Cancer. COVID.
Asthma. Schizophrenia. Measles. Sickle cell anemia. Obviously there are lots more diseases,
but even just these show how different diseases can be in their symptoms,
how debilitating they are, how long they last, how you get them. So what do they all have in common,
other than that we call them diseases? Hi, I’m Kate and this is MinuteEarth.
And I know what you might be saying: Who cares if something is *officially* a disease? And I
get it…here at MinuteEarth, we love poking at definitions, sometimes more out of curiosity
than utility. But defining “disease” is actually a really important issue that lots of people
in the medical community grapple with. That’s because giving a condition – say,
asthma – the official label of a “disease” has all sorts of consequences. It suggests
the condition needs to be treated, and affects how much money gets directed toward understanding
it and working on cures. It affects whether a person with it might get time off work,
or get the cost of their care covered. And it matters in a more fundamental way:
how others think about people with it, and even how people with it think about themselves. So
figuring out what counts as a disease – and what doesn’t – is kind of a big deal.
When the official panels tasked with making those decisions sit down to look at a potential disease,
they generally use three main criteria: a disease is a specific, known abnormality
in the body’s structure or function that affects the organism in a negative way and is not just the
result of an injury. Which seems…straightforward. Measles is not how the human body normally works,
it makes you feel pretty bad, and it’s not due to an injury – it’s a disease. Cancer also:
not normal, makes you feel terrible, not caused by an injury…disease. A broken bone
isn’t normal and feels very negative, but it IS the result of an injury, so it’s not a disease.
But once you start poking that definition with some less-obvious test cases – like,
is acne a disease? Lead poisoning? Autism? Pregnancy? Aging? – things
get really complicated really quickly. Like, is aging “abnormal”? On one hand, everybody ages,
so it’s a totally normal experience, but on the other hand, compared to a healthy young person,
aging seems like a very abnormal state – therefore like a disease. Then, there’s what
it means to affect someone in a “negative” way; like, many people argue that autism shouldn’t be
considered a disease because it affects people in a bunch of different ways, not a simply – or even
overwhelmingly – negative way. So the lens through which you’re looking can affect whether or not
something seems like it’s abnormal or negative or even the result of an injury – and therefore
whether or not it should be considered a disease. And that lens can change, too. For a long time,
obesity and addiction weren’t considered diseases because people assumed they
were the result of personal decisions, not “abnormalities of structure or function”.
But as we’ve learned more, we’ve discovered that they do have biological underpinnings,
so both are now considered “diseases” by basically every major decision-making body. Homosexuality
has gone the other way; it’s gone from being seen as “abnormal” to recognized as just another aspect
of the incredible diversity among humans – and has therefore lost the official label of “disease”.
In the end, though, the hardest thing about determining whether something is a disease or
not isn’t defining the lens we’re using, or how that lens changes, but the fact that “disease”
is a concept that we humans made up. It’s not like there’s some single *thing* that all diseases have
that we just need to pin down; we’re trying to build a box around stuff that has no natural box,
in a way that includes certain kinds of stuff, and excludes others. Is that a worthwhile task? Maybe,
but it also probably isn’t going to yield perfectly clear results.
Hey, hang on…we aren’t quite done serving up our food for thought. See,
we’ve discovered that not all of you know that we’ve cooked up a new channel, all about the
science of food and cooking. Over at MinuteFood, we’re spilling the beans on all the weird and
wonderful science that happens in the kitchen – from the chemistry of cast iron to the biology of
garlic to the physics of air fryers - all with the goal of helping you cook and eat more delicious
food. Maybe I’m biased, but I think MinuteFood is the best thing since sliced bread. And I think
it could be your cup of tea, so go check out what we’re serving up at youtube.com/minutefood