Illness, Disease and Sickness Are Three Different Things
Illness is being unwell. Medical sociology draws a careful line between the experience of illness and the pathology of disease.
Illness is the state of being unwell. Writers on medicine draw a useful three-way distinction: *disease* is the underlying pathology a doctor can identify, *illness* is what the patient experiences, and *sickness* is the social role that follows — the sick note, the missed work, the sympathy. Someone can have a disease without feeling ill, and feel ill with no disease found.
- The state of being unwell. *A long illness.*
- A particular disease. *A serious illness.*
- Mental illness — illness affecting thought or mood. *Support for mental illness.*
Word forms
| Form | Word | Example |
|---|---|---|
| Noun | illness | A short illness. |
| Plural | illnesses | Childhood illnesses. |
| Adjective | ill | She feels ill. |
| Related | disease | Heart disease. |
| Related | sickness | Motion sickness. |
How it is used in a sentence
- He returned to work after a long illness.Countable when a particular episode is meant.
- Mental illness affects one in four adults each year.A widely cited figure.
- She is off with a stomach bug.Everyday speech avoids the formal word.
The three words compared
- Disease — the pathology, identified by tests and examination
- Illness — the patient's experience of being unwell
- Sickness — the social role and its consequences
- Condition — a neutral word, often for long-term states
- Syndrome — a recognised group of symptoms without a single known cause
From *ill*, borrowed from Old Norse *illr*, bad, plus *-ness*. The Norse word meant evil or bad before it narrowed to unwell in English.
Ill or sick?
British English uses ill for unwell and sick mainly for vomiting. American English uses sick for both.
Illness or disease?
Disease names what is wrong biologically. Illness describes how it feels to the person who has it.