What's the difference between stress and anxiety?

Stress is a response to an identifiable external demand and usually eases when the demand passes. Anxiety persists without a clear trigger, is disproportionate, and often features anticipatory worry, physical symptoms, and avoidance behaviour.

A useful marker is function and duration. Anxiety that persists most days for six months, is hard to control, and causes avoidance or impairment suggests a disorder rather than a reaction.

Physical features are common: muscle tension, disturbed sleep, irritability, restlessness and difficulty concentrating.