Are we becoming increasingly intolerant, or is it the case that up to 20 per cent of us fall into the category of Highly Sensitive People, who are overwhelmed by the hurly-burly of modern life?

In psychotherapist Dr Elaine Aron book, The Highly Sensitive Person: How To Thrive When The World Overwhelms You, she offers the theory that some people are born with a more sensitive nervous system - and are more easily stimulated to panic, intolerance and general over-reaction to modern living.

Dr Aron suggests that HSPs share a fear of violent films, a dislike of loud noises, and a regular need to be alone.

But Dr Aron insists that HSPs also embody plenty of positives. There are suggestions of a 'rich, complex inner-life' and 'being moved by the arts and music'.