Educational reference
About this symptom
An exaggerated startle response is reacting more strongly than the situation warrants to something sudden: a door closing, a phone ringing, someone approaching unnoticed.
Startling is normal and protective. What marks this out is the intensity, how long it takes to settle afterwards, and that it happens in ordinary safe situations. People describe jumping at small noises, colleagues learning to announce themselves, or feeling shaky for minutes after a trivial surprise.
It belongs to the group of experiences described as heightened arousal, and it commonly accompanies feeling on edge, disturbed sleep and difficulty concentrating. It is recognised after trauma in particular, where the body's threat-detection remains set high after the danger has passed.
It is not something a person can simply decide to stop, and it tends to improve as the underlying condition is treated rather than through effort of will.