BetterThe three words travel together. They get used one for the other, as if they described degrees of the same thing, a little tired, very tired, completely spent.
They do not. Two of them name disorders. The third, according to the World Health Organization, is not a medical condition at all.
Anxiety disorders are the most common mental disorders in the world: 359 million people in 2021. Depression carries a duration marker, most of the day, nearly every day, for at least two weeks. Burnout is not classified as a medical condition: the WHO files it as an occupational phenomenon, tied to work and to work alone.
The starting pointWhy the three words blur together
They blur because the sensations overlap. Exhaustion, sleep going wrong, concentration giving way, the sense that everything costs more effort than it should, all three can produce that, and someone living through it has no reason to sort them out.
But the words do not sit in the same place. Two describe disordersstates with criteria, and with treatments. The third describes a situation: a state produced by a job. Confusing them is not a vocabulary problem. It sends people looking in the wrong place.
The most commonAnxiety: when fear stops switching off
Everyone feels anxiety. It is a normal reaction, and a useful one: it prepares the body for something that matters. What the WHO calls an anxiety disorder is something else, fear and worry that are intense and excessive, hard to control, causing real distress, and lasting a long time if nobody treats them.
The line is not drawn by how strong it feels in the moment. It is drawn by whether it switches off on its own.
The WHO does not use “anxiety” as one single label either. It lists several distinct disorders: generalized anxiety disorder, panic disorder, social anxiety disorder, agoraphobia, separation anxiety disorder, specific phobias and selective mutism. They do not feel alike, and they are not treated alike.
The number worth remembering is the second one. Effective treatments exist, and three people in four who need them get nothing. The WHO points to limited awareness, underinvestment, a shortage of trained providers, and stigma. That last item is the only one on the list an ordinary conversation can move.
The duration markerDepression: not a stronger sadness
This is the most persistent misunderstanding of the three. Depression is not sadness turned up. The WHO states it plainly: it is different from regular mood changes and feelings about everyday life.
What it describes is a depressed mood or a loss of pleasure or interest in activities, over long periods. Note the or: someone can be depressed without looking sad. Losing all interest is enough.
Symptoms last most of the day, nearly every day, for at least two weeks.
That is the sentence that separates a hard fortnight from a depressive episode. It is not a test to run on yourself, it is the marker that says when the question deserves to be put to someone qualified.
Alongside mood, the WHO lists: poor concentration, excessive guilt or low self-worth, hopelessness about the future, thoughts of dying or of suicide, disrupted sleep, changes in appetite or weight, and fatigue or low energy.
The surpriseBurnout: the word that is not a diagnosis
Here is the part almost nobody knows, and it is written in black and white in the WHO's own classification.
In the International Classification of Diseases, burnout does not sit in the chapter on diseases. It sits in the chapter on factors influencing health status or contact with health servicesthe chapter for reasons people consult that are not themselves illnesses.
The WHO defines it as a syndrome conceptualized as resulting from chronic workplace stress that has not been successfully managed.
It is described along three dimensions:
- a feeling of energy depletion or exhaustion;
- increased mental distance from one’s job, or negativism and cynicism about it;
- reduced professional efficacy.
And the restriction that follows is the one that gets ignored. The WHO specifies that burnout refers specifically to phenomena in the occupational context and should not be applied to describe experiences in other areas of life.
So there is no parental burnout, no relationship burnout, no burnout of caring for a relative, not under this word. Which does not mean those forms of exhaustion are not real. It means the word does not cover them, and that naming it that way says nothing about what to do next.
Why does this matter in practice? Because if burnout is produced by work, then part of the answer sits in the work, not only in the person. Treating it as an illness of the individual quietly hands the whole problem to whoever is worn out.
What it changesWhy this changes how you speak to someone
You are probably not reading this to diagnose anyone. Nobody here can do that, and this article does not try. What the distinction changes is smaller and more useful: what you say, and what you suggest.
One last thing that costs nothing: the three words are not ranks. Someone is not “only” anxious, and not “already” depressed. They describe different things, not stages of the same descent.
There is no worldwide helpline, and numbers change from one country to the next. Two markers hold everywhere.
If there is immediate danger, call your country’s emergency number.
Otherwise, Find A Helpline lists more than 1,700 free and confidential helplines in over 175 countries. You pick your country, it shows what exists near you, with opening hours. The site itself is in English, but the lines it points to are local.
This is not a clinical recommendation. It is the one international directory that states it verifies its data with the helpline organisations themselves and maintains it daily.
QuestionsFrequently asked questions
Anxiety and stress: are they the same thing?
No. Stress is a reaction to something happening now, and it fades when the situation passes. An anxiety disorder is fear and worry that the WHO describes as intense, excessive, hard to control, and long-lasting if left untreated. The difference is not how strong it feels in the moment: it is that it no longer switches off on its own.
How long does it take before it is called depression?
The WHO gives a precise marker: symptoms last most of the day, nearly every day, for at least two weeks. That is what separates a depressive episode from ordinary mood changes. Two weeks is not a threshold to apply to yourself, it is a marker for when the question deserves to be put to someone qualified.
Is burnout an illness?
No, and that is official. In the WHO's International Classification of Diseases, burnout sits in the chapter on factors influencing health status, not in the chapter on diseases. The WHO writes that it is not classified as a medical condition. It is an occupational phenomenon, described as resulting from chronic workplace stress that has not been successfully managed.
Can you have parental or relationship burnout?
Not in the WHO's sense. Its definition states that the term refers specifically to the occupational context and should not be applied to describe experiences in other areas of life. That does not mean a parent's exhaustion is not real, it means it is not covered by that word, and using the word says nothing about what to do next.
How many people are affected worldwide?
The WHO puts at 359 million the number of people who had an anxiety disorder in 2021, making it the most common of all mental disorders. For depression it gives 332 million people, or 5.7% of adults, 4.6% of men and 6.9% of women. Burnout has no equivalent figure, precisely because it is not a disease that gets diagnosed.
Why are so few people treated?
The WHO writes that highly effective treatments for anxiety disorders exist, and that only about one person in four in need, 27.6%, receives any treatment at all. It attributes the gap to limited awareness of these disorders, underinvestment in mental health, a shortage of trained providers, and social stigma.
Read nextRelated
Sources
- Anxiety disorders, World Health Organization, 8 September 2025
- Depressive disorder, World Health Organization, 29 August 2025
- Burn-out an “occupational phenomenon”, World Health Organization, ICD-11
About this article. General and educational information, accurate as of the date shown. It describes how three terms are defined by the World Health Organization; it is not a diagnostic tool and does not replace an assessment by a qualified professional. Definitions and figures may be revised: the WHO fact sheets linked above always carry the current version.
Spotted an error or an out-of-date figure? Write to us: we will correct it and re-date the article. Our texts are written with the help of artificial intelligence and checked against official sources before publication, but a figure or a definition can change without us catching it. If anything here does not match what an official body tells you, they are right.