Anxiety can develop for many different reasons. Sometimes there’s a clear trigger. Other times, it can seem to come from nowhere.

This can feel confusing or frustrating, but it’s very common.

Life stresses

Anxiety is often linked to what’s happening in your life.

Things that can trigger or increase anxiety include:

Ongoing stress can keep your nervous system in a heightened state, making it harder to relax or feel safe.

Personality and past experiences

Some people are naturally more sensitive to stress, feel things more deeply or worry more.

Early experiences also matter. Growing up without steady emotional support, or living through trauma or instability, can affect how your body responds to stress later on. These experiences can shape your sense of safety in the world.

Physical health and other factors

Sometimes symptoms of anxiety can be caused or worsened by physical health issues such as:

  • thyroid problems
  • anaemia or low vitamin B12
  • chronic pain
  • side effects of medication
  • alcohol or drug use
  • hormonal changes such as perimenopause or menopause

A GP can help check for physical causes and talk through what support might help.

When there’s no clear cause

Not everyone knows why they feel anxious. This doesn’t mean you’ve done anything wrong or are “broken”. Anxiety is complex, and it can develop slowly as a learned response to stress or difficult experiences over time.

Last updated: February 2026