Stephen Fry openly uses his own experience of mental ill health to consider the ever-changing way in which what's commonly called madness is talked and written about. With the help of comedienne and former psychiatric nurse Jo Brand, the controversial comedienne Maria Bamford and the writer Jon Ronson.

What we mean by "mad" changes constantly. Outmoded diagnoses - moron, hysteric, schizophrenic - turn into insults. But our dissociation of madness seems to downgrade its seriousness. As Dr Oliver Double from the University of Kent describes, today we use its terminology to describe everything from being mildly annoyed to being creatively exhilarated or intoxicated. A rave in the 1990s was "mental". A recent sit-com was "hysterical". The creative endeavors of an artist are "totally bonkers". Comedians channel madness, real and metaphorical. Even an innocent game of Krazy golf borrows from the looney lexicon.

Jess Thom is a writer and comedian and the founder of Tourettes Heroes. She talks about what language means for someone with tourettes syndrome and why she wants people to feel free to laugh at what she describes as her "crazy language generating machine" - the propensity to suddenly shout out bizarre words and phrases.

Nowadays, we're all too ready to use what we think are modern technical terms - bipolar, sociopathic, narcissistic, obsessive compulsive, on the spectrum - revealing much about the hyper self-conscious, self-examining era in which we live. The new pseudo-clinical lexicon has permeated informal discourses far beyond the realms of psychiatry.

It's enough to drive you mad. Metaphorically, of course.

A Testbed production for BBC Radio 4. Show less